Unbalanced heat in 4 unit with 1 thermostat.

SteamingatMohawk

Situation: ~100 year old 2 family house converted to 4 units (up/down, front/back). New tenant in up front apartment with the lone thermostat. Heat in the house is extremely unbalanced, going from too low to too high.

A new tenant moved into the apartment. He decided to use the living room as his bedroom. I had no objection as long as he follows my rules. The living room has a large center window with a smaller window on each side. So he gets sick and has a 102 fever. The doctor and his brother tell him to stay indoors (a couple of weeks ago) and open the windows on a nice day to get fresh air. Not only does he open the smaller windows, he puts a box fan blowing air out of the living room.

The lone thermostat for the building is in that living room on the opposite wall about 15 feet away. The system worked flawlessly for the last several years.

In addition to the window adventure, the head of the bed is about a foot from the radiator. Holy cow!

I explained how the steam heat system works to the tenant and his brother. The tenant stopped having the windows open for extended periods. That did not solve the issue. He then moved the bed to about 6 feet away from the radiator, perpendicular to the front of the house. Today, other apartments were cold, even though the temperature and thermostat setting were OK. I have a wireless wifi thermostat so I can monitor the system using an app on my phone.

Last week, I found the rear main vent appeared to not be working. I was unable to get an exact replacement locally and installed a knockoff one with 1/3 the capacity on the main to the back of the house (I didn’t know the capacity until I got home and looked it up in the Gill report). I had to go to Supply House to source what I want after failing to find one at 5 local plumbing houses and the big boxes. I will install it today.

This morning (outside temperature in the 20s) two apartments were in the mid 60s and the apartment with the thermostat was at 69. That has been the thermostat setting where everyone has been comfortable…I go by comfort not temperature because the thermometers I have in the apartments are not consistent, sometimes different by 4 degrees.

I am going to check out the vents to make sure they are working, but the cold apartments overheat when the heat is on, so I don’t think that’s an issue.

The front main vent was working, but since I am going to change the other one I will change it as well. I also have a second main vent after the last riser on the front main. I will check that.

This is driving me nuts because once the window and bed problem were resolved, I expected the system to settle out (given this is shoulder season). It didn’t.

I don’t live there and only have the thermostat setting and temperature from it for monitoring and whatever the tenants tell me. They are perfect tenants, and been in the house for more than 4 years, so I trust they are not messing around without telling me.

I wonder if this overheating could have done something to any of the vents, like getting clogged, etc.

I am considering a few things.

Buy wifi thermometers for the apartments, so I can monitor them without bothering the tenants. I need recommendations on make and model from HHers.

Consider TRVs to limit the overtemperature, but have no experience with them. I realize they may be able to control it, but can’t allow heat if the system is not firing. I need recommendations on make and model from HHers.

The only other idea is to find a way to have sensors in each apartment be able to call for heat and if needed TRVs in those rooms to limit overtemperature. Matching the two could be tricky, if not impossible…TRVs shut with sensors calling for heat…doesn’t sound too good. This would simulate zoning to some extent, but I don’t have a good feel for how the boiler would handle a call for heat at only one apartment. It almost seems it could make things worse.

It took a lot of troubleshooting several years ago to get the system working fine and has been until this Fall.

Suggestions?

EdTheHeaterMan

My son has several sensors around his home that will let him know if there is a low or high temperature condition in any of the rooms that have those sensors, They are not connected to the HVAC system in any way but he can ask Alexa "what is the temperature in the office?" or look at all the sensors on an app. I'll ask him about that system. As far as TRV for one pipe steam systems, you will need to get the one that fits on the steam vent for each radiator. https://www.supplyhouse.com/Macon-Controls-MAC-OPSK-W-EVO-1-8-Threaded-One-Pipe-Steam-Straight-Valve-Assembly-with-EVO-28-Operator.

EdTheHeaterMan

got this reply from my son:
Govee WiFi Thermometer Hygrometer, Indoor Smart Humidity Temperature Sensor with App Notification Alert, 2 Years Free Data Storage Export, Remote Monitor for Home Greenhouse Basement Pets

SteamingatMohawk

Thanks. Today it has 5461 ratings at 4.4 of 5

dabrakeman

More expensive option but an Ecobee thermostat with multiple remote sensors can allow you to not only monitor the temperature in different areas but control the boiler via temperature from the thermostat, from any of the remote sensors or any averaged combination of some or all of the sensors and thermostat.

SteamingatMohawk

From your description I take it to mean I manage the system based on the info I am given by the sensors, then make a decision to turn on the heat. The sensors do not automatically individually control the heat.

Can you give me a model number that will do the base and 3 additional sensors? I can then get the manual and better understand how it works.

Thanks,

SteamingatMohawk

I did some investigating and found that not only was the rear main vent not working, so was the front main vent. I replaced both as I mentioned above. I also removed the Gorton#2 that is after the last riser in the front main and made sure it rattles, passes air and will not pass air if I turn it upside down.

Got my fingers crossed this will improve the situation.

dabrakeman

Making sure your main venting is working and adequate is always the first step in balancing any system.
As far as the Ecobee not only can you see all the various temperatures from the different sensor locations as well as where the thermostat is located but you can also assign what sensor source you want use to control the boiler. Could be just the thermostat. could be just one of the various sensors. could be an averaged combination of all or some of the sensors and thermostat. Ecobee 3 Lite then add the remote sensors you want.

SteamingatMohawk

Does anyone know of a credible steam guy in the Albany/Schenectady area?

I have communicated with Charlie from WMASS, but he doesn't do my area.

SteamingatMohawk

My problem remains. Apparently, the work on the main vents didn't make a difference. Last evening I was thinking about what has changed with the previous tenant leaving and a new one onboard.

The controls are a Honeywell Focus Pro YTH5320R1000. Is there any known problem with this equipment.

With the previous tenant, she had the thermostat (battery powered and wireless to the EIM) in a different location. I had it on the living room wall somewhat near the kitchen and when she cooked a lot, the heat would not come on. Other tenants justifiably complained. So I had her locate it in a different part of the living room. Fortunately my decision to go with a non-wired thermostat paid off. It was kept between 6 and 10 feet from the radiator most of the time. No problem for 4 years.

She had curtains on the wall in the living room. I think they were fairly heavy, but have asked her about them. She has not yet replied.

She had a big couch (heat sink) and he has his twin bed in the room about half way between the radiator and thermostat.

With the new tenant, I put the thermostat back on the wall and he hasn't gotten curtains yet.

I'm wondering what effect these changes could make to how that room heats up. What has me totally confused is with the thermostat set at 69, when the heat comes on the room can heat up to 71-72 range by the thermometer in the thermostat. I don't understand how the temperature could overshoot the thermostat setting by that much after she moved vs. while she was here.

The vent valve is a Heat Timer fully open and been that way for the 4 years. I removed it and checked that it passes air like others I have on hand. Could the residual heat in the system be bleeding enough through the Heat Timer after the boiler shuts off? With no curtains, it seems the heat loss is greater than with them.

I replaced the batteries in the thermostat a couple of weeks ago and will check them. I will probably also move the thermostat from the wall to a location similar to where the previous tenant had it. But I am not sure that explains the overshoot.


For info this room is on the second floor facing North with an unheated attic above it (100 year old insulation in the space between joists). The stairway to the apartment is heated and the door to the apartment is closed except for entering and leaving.

ChrisJ

Can you change the CPH setting on that thermostat?
That's the first place I'd look. Once changed it'll take a little while for things to settle back down also.

I'm using a Honeywell Prestige with 3 wireless sensors placed in different rooms which allows it to average the temperature from 4 locations. In my situation, even though I keep 1 of the locations 5 degrees colder than the others it doesn't matter because it's just looking for a difference to turn on and off. It just makes the display on the thermostat read lower once I have it set where I want.

If you can't change the CPH setting, that's the very first place I'd start. The Prestige would allow you to select 2 CPH which most don't, or 3. I usually run 2 my self but if it's really cold out I'll increase it to 3 CPH.

The CPH setting simply makes the thermostat more sensitive and causes it to shut the boiler off earlier. In fact, when first changed it'll likely short cycle a few times and barely heat.

SteamingatMohawk

Today I was able to do a "natural" call for heat run and witness the system performance. Short version...the response of the thermostat to the temperature rise seems way slow. With several laser thermometer tool readings in the 73is range, the thermostat temperature had barely reached 70. I think this might be unusual, so I am going to look at the equipement specs and call Resideo to see what they have to say.

The rest of the performance was consistent with my expectations.

More to follow and thanks for the feedbacks.

gfrbrookline

I have had good luck with my Honeywell vision pro with multi wireless remote sensors so I can turn them on and off to account for changing conditions in different units. From everything I have read on the page the modern learning thermostats do not work well with steam heat.

dabrakeman

Sometimes a thermostat mounted to a wall will lag actual room temperature due to cold air in the wall behind the thermostat. Even plaster walls can be a big heat sink resulting in temperature hysteresis. I tried stuffing insulation behind my thermostat but in the end like @gfrbrookline I too now use remote sensors to control the boiler. They improved this situation considerably since I can sit them in locations more representative of the living space I wish to control.

SteamingatMohawk

I think I have eliminated any mechanical issues and now am focussing on the real temperature and how the thermostat is working or not working.

For anyone interested, go see my separate discussion under Thermostats and Controls.

Honeywell FocusPro TH5320 thermostat with EIM

SteamingatMohawk

@ChrisJ I know you will have this answer at your finger tips. Does your Honeywell Prestige with 3 wireless sensors work with the Honeywell EIM that I have?

I just invested in direct replacement for my existing thermostat in case I can prove it is not working well enough to keep it in service.

SteamingatMohawk

@EdTheHeaterMan How long has your son had the sensors and has he had any problems? I found a 6 pack on the internet so I guess I could have one in each apartment. I'm not sure what the app can handle.

ChrisJ

SteamingatMohawk said:

@ChrisJ I know you will have this answer at your finger tips. Does your Honeywell Prestige with 3 wireless sensors work with the Honeywell EIM that I have?

I just invested in direct replacement for my existing thermostat in case I can prove it is not working well enough to keep it in service.

It has an EIM, but it looks different than yours.
Not sure if they're interchangeable.

SteamingatMohawk

Honeywell FocusPro TH5320 thermostat with EIM

ChrisJ

SteamingatMohawk said:

Honeywell FocusPro TH5320 thermostat with EIM

This is what the EIM that came with my Prestige looks like.




They're all Redlink apparently but I have no way of knowing if that will work with the EIM to a FocusPro.
I'm curious, what's the reason you ask?

SteamingatMohawk

Curiosity, plus maybe there is something different with this model if it was created after the EIM I am using.

When I changed Setup function 32 from 0 to -3, the boiler runs more often which I expected, if it does the same thing as a heat anticipator.

But, the odd thing is the temperature reading on the thermostat is always the same number equal to the thermostat setting. It does not change from beginning to end of a heating cycle.

ChrisJ

SteamingatMohawk said:

Curiosity, plus maybe there is something different with this model if it was created after the EIM I am using. When I changed Setup function 32 from 0 to -3, the boiler runs more often which I expected, if it does the same thing as a heat anticipator. But, the odd thing is the temperature reading on the thermostat is always the same number equal to the thermostat setting. It does not change from beginning to end of a heating cycle.

That's all digital Honeywell thermostats even a prestige.  I first noticed it on my green screen vision pros.  They would lie up to something like 2 degrees and then it'll suddenly change and display the real temperature rather than the set temp.

I find a cph setting of 2 to work best most of the time.  3 seems to be a tad too sensitive.  Also keep in mind when you change that it takes time to settle down because it adapts over time.

SteamingatMohawk

@ChrisJ I wonder what would happen if I set function 32 Temp. Display offset (indoor) back to 0 from -3 and changed function 5 "Stage 1 heat cycle (CPH: cycles per hour) to 2 or 3. Maybe the thermometer in the thermostat will respond to temperature and setting a specific CPH accomplishes the same thing as changing function 32

SteamingatMohawk

This morning one of my tenants said she can tell the difference in the heat between times when the boiler level is high (like after an autofeed) compared to when it is low (like just before an autofeed). She has been a tenant for 8 years and is pretty savvy about the system. Well taught by her father.

Has anyone come across this idea?

Have a great day!

SteamingatMohawk

Today, I contacted Resideo again and was informed the function 32 Temp. Display Offset does not do what the first rep told me about mimicking a heat anticipator. Today's guy said it merely takes the temperature reading and adds or subtracts whatever the offset is to what the readout says. I didn't think the first guy was right, but was in no position to argue the point.

So, this afternoon, I changed the offset to the factory amount of "0". The second rep said the offset function exists so that if people have multiple thermostats, the Honeywell can be adjusted to match the other(s) so they read the same for the same conditions. It better matches the title, but I don't quite understand how that is of value since the tstats would not be very close together.

Personal counterpoint...I spent some $$ to buy +/-0.5F accuracy thermometers so I can compare rooms in my apartments to the same "standard". I put all 5 of them on my kitchen table, lest them stabilize for a while and they all read the same number...close enough for me.

The menagerie of thermometers the tenants had in the 4 apartments read up to 4 degrees different from my laser infrared thermometer. Science triumphs again.

ChrisJ

SteamingatMohawk said:

Today, I contacted Resideo again and was informed the function 32 Temp. Display Offset does not do what the first rep told me about mimicking a heat anticipator. Today's guy said it merely takes the temperature reading and adds or subtracts whatever the offset is to what the readout says. I didn't think the first guy was right, but was in no position to argue the point. So, this afternoon, I changed the offset to the factory amount of "0". The second rep said the offset function exists so that if people have multiple thermostats, the Honeywell can be adjusted to match the other(s) so they read the same for the same conditions. It better matches the title, but I don't quite understand how that is of value since the tstats would not be very close together. Personal counterpoint...I spent some $$ to buy +/-0.5F accuracy thermometers so I can compare rooms in my apartments to the same "standard". I put all 5 of them on my kitchen table, lest them stabilize for a while and they all read the same number...close enough for me. The menagerie of thermometers the tenants had in the 4 apartments read up to 4 degrees different from my laser infrared thermometer. Science triumphs again.

Can you give a link to the thermometers you bought?

I've never been able to find ones that are that accurate and would like a few.

BobC

Be careful laser guns are dependent on the color of the target, mine don't like anything shiny.

Bob

ChrisJ

BobC said:

Be careful laser guns are dependent on the color of the target, mine don't like anything shiny.

Bob

They also don't like sudden changes in ambient temperature.

SteamingatMohawk

@ChrisJ I sent you the link in a message. It has the price, so it's not fair game for posting. I got them for 20% less.

It's the Govee multiple sensor, with a +/-0.5F accuracy.

Govee WiFi Hygrometer Thermometer 6 Pack H5100, Indoor Wireless Temperature Humidity Sensor Monitor with Remote App Notification Alert, 2 Years Free Data Storage Export, for Home, Greenhouse

They can monitor up to 10 sensors via the app.

SteamingatMohawk

Its similar to what @EdTheHeaterMan posted earlier in this discussion.

SteamingatMohawk

Relative to the color comment, some of my system is copper, both shiny and dull. What I do is shade the target from any light source and make sure I am confident I am reading a "true value".

I use it a lot when I am checking how quickly the system warms up...its better than burning my fingers.

If I want to know when the steam is actually getting to a specific location, I read only the bottom of the main to see when the condensate begins flowing back to the boiler. Then a short time later the whole pipe is too hot to touch. I avoid, where possible, monitoring fittings because the extra metal slows down the response to heat.

Yesterday, I made two changes to the system and when I restarted the system I made an interesting observation, I hadn't thought about all these years. Once I confirm I am not fooling myself, I will post the info. It didn't become obvious until I had two temperature sensors in the same room, but in different locations.

This escapade was driving me nuts, because the thermometers in the apartments did not have consistent readings. I found some inexpensive ones from AcuRite that are +/-0.5F accuracy, most are between +/-1.8F and +/-2F.

The same thing with the infrared thermometers, but even worse accuracy. Check out my "test" on my kitchen table. Some times they were 4F apart and I was using the grey one. Now I use the yellow one and leave the grey one home for when I make pancakes and waffles.

SteamingatMohawk

Yesterday (12/28/2023), I was at the house twice. I went there because the second floor living room which has the thermostat was in the 80s, while the two first floor living rooms were in the mid-70s. I had been trying to boost the first floor temperatures without excessively raising the second floor temperature, then hoping the second floor room would cool down faster than the first, since it is the coldest room in the house. With the warm temperatures (mid 40s) that idea is not working. Call it the definition of insanity, doing the same thing over and over and expecting a different result!

So, today’s request is this:

The first and second floor room temperatures go up and down (duh), but there is an “offset” because the second floor room became hotter for some reason. How do I get the rooms to be at the same temperature at the same time?

It seems there is more than one approach:

Heat up the first floor without heating up the second. How do you do that when the control is the second floor? Run the heat with the second floor radiator isolated until the first matches?

Cool the second floor without cooling the first. Open the windows in the second floor to bring the temperature down to the first floor level?

Once they are matched, the system hopefully can stay balanced or at least have a way to “easily” bring them closer.

Because of significant issues with the second floor tenant, ideas that don’t involve going into that apartment might be easier to accomplish.

I have been dealing with this off and on since mid-October. You can see that in my other discussions. So far, I haven’t proved there is anything wrong with the functioning of the system, both mechanical and electrical.

I’m open to any ideas (even selling the house). But that won’t happen until I solve this imbalance.

jesmed1

As a homeowner/engineer, I think you need a multi-prong approach, as it doesn't look like there's one "silver bullet."

1. Switch to a multi-sensor averaging thermostat as suggested above by others. @dabrakeman suggested the Ecobee. @ChrisJ suggested the Honeywell Prestige that he uses successfully with multiple sensors. @gfrbrookline suggested the Honeywell Vision Pro. I haven't used any of those, but if I had your problem, I'd try the Ecobee, as it has a nice online interface. The advantage of the multi-sensor averaging is that you get a "happy medium" average temperature throughout the building, where no one unit is too hot and no one unit is too cold.

2. Once you have the multi-sensor thermostat installed and the building temps have stabilized at the "new normal," find which units are still overheating and install TRV's on selected radiators (maybe the biggest one) in those units to minimize the overheating. The TRV's should bring down the higher temperature excursions and keep those units closer to the average building temperature. https://heatinghelp.com/systems-help-center/rethinking-trvs-for-steam-systems/ (Note that the article says TRV's won't work well if the system pressure is over 1-2 psi on a one-pipe system).

The combination of a multi-sensor averaging thermostat and some TRV's in the warmest units should get you close to where you want to be, I would think.

Again, not a heating pro, just a mechanical engineer homeowner, but that's what I'd try next.

SteamingatMohawk

Thanks. What is most disconcerting is that prior to this tenant moving in in October, the past 4 year history of the system is no problems, with one exception.

The exception is because of the arrangement of the apartment living room and kitchen and where I located the thermostat, when the tenant would cook, sometimes the thermostat would warm up enough to prevent the heat from coming on and the downstairs back tenant's apartment would get colder.

The solution was to relocate the thermostat (which is battery powered with a wireless connection to the control panel in the basement and a gateway so I can monitor/control the system with my cell phone) to a different place in the living room (i.e., no rewiring...that's why I bought it). One of the tenants casually mentioned to me they have occasionally put it in the bathroom, which is at the opposite end of the living room further from the kitchen stove.

When the new tenant moved in, I put the thermostat back at the original location and have not relocated it. I am awaiting an overdue delivery of a Govee 6-sensor thermometer kit that I can use to try to find a better place in the living room, so it doesn't need to be moved. The dynamics of the room are interesting.

A few minutes ago, I finished plotting the thermostat setting vs the thermometer reading on the thermostat and a separate sensor in a different place in the room (without cooking or any additional heat source in/near the room). The thing I don't care for with the separate sensor is it is at an outside wall, but on a shelf not mounted on the wall.

What is interesting about how the living room heats under these conditions is how long it takes for the readouts to sense the heat from the radiator and then how the "plume of heat" travels in the room eventually being sensed by the two thermometers.

jesmed1

We've had similar problems in our 4-unit condo building, but not as extreme. We have 4 units, 2 on each side of the building, with 2 separate heatings systems, one per side. The thermostats for both systems are in the first-floor units.

So I've had to do some balancing, too. The most important factor I've found is the secondary heat sources (like the kitchen stoves) that produce heat that eventually wafts into the thermostat room, suppressing calls for heat.

We have a Jotul natural gas direct vent "stove" heater on an enclosed rear porch at the back of our unit, 40 feet away from the main thermostat, and separated by two rooms and a hallway. Yet, if doors are left open, heat from the Jotul will eventually waft into the dining room where the thermostat is, and suppress heat calls. Eventually the upstairs unit will cool 2-3 degrees because the boiler isn't coming on.

So you are finding the same problem with your tenants cooking, etc. We've solved the problem here by having several doors separating the rooms and making sure those doors are closed while the Jotul is on.

Also, we've found that you get more even heat distribution by not allowing too much time between boiler runs. The longer the boiler isn't running, the more time there is for uneven heat losses in the various units. And the longer the boiler doesn't run, the longer it has to run to satisfy the thermostat. And longer boiler runs can cause some units to overheat.

So I've had to find the right balance by choosing the "swing" setting on the Tstat appropriately. Too low a swing means the boiler doesn't run long enough cycles to be efficient. Too high a swing means the boiler has to run longer, increasing the chances that one unit will overheat. I've found that swings of 0.5-0.75 degrees work best for our system, which is an old gravity converted cast iron hot water system with cast iron boilers.

With those settings, we can maintain 68-70 in both upstairs and downstairs units over a wide range of outdoor temps, even though the thermostat is in the downstairs unit.

SteamingatMohawk

This might help visualize the arrangement, cropped for privacy.

This photo shows the stove in the very small kitchen on the other side of the wall from the thermostat. The wall on the right side has another door to the right to the bathroom (100 year old house) and the wall on the left side is the outside wall. Behind the camera is the front of the house with 3 windows and the radiator.

jesmed1

Just remember that the graph you posted is for an unsually large temperature rise (+10 degrees) which you normally won't have, so the response time is going to be much longer than normal. From your pic, it looks like the rooms are fairly small, and you said you have 3 rads on the wall opposite the Tstat. So under normal operation, where your Tstat is maintaining like +/-0.5 degrees, the response time should be quite good. And while the kitchen range is nearby, it looks to be fairly small, so unless the tenant is baking/roasting with the oven on for extended periods, it may not be a problem.

We have one rad in the dining room where the Tstat is, and one larger rad in the adjacent living room with a large cased opening through which heated air passes easily, and the response time of our cheapo thermostat is quite good, with no overshoot.

I know others on this thread say good things about their Honeywell thermostats with multiple sensors, but I've had not-so-good experience with Honeywell T6 Pro and other cheaper Honeywell units. As we've discussed previously in this thread, they don't always correctly report actual room temp, and the Honeywells I've had don't allow you to adjust the swing settings, so my personal preference is to avoid Honeywell products entirely, but YMMV.

SteamingatMohawk

Has anyone come across a wireless wifi radiator vent that can be monitored by an app on a cell phone?

jesmed1

Here's one that seems to have mostly positive reviews:

https://www.amazon.com/Shelly-Wi-Fi-Operated-Thermostatic-Intelligent-Temperature/dp/B09RPVRQ3F/ref=sr_1_5?crid=1VPKOC13Q7U5E&keywords=shelly+trv&qid=1703868300&sprefix=shelly+trv,aps,110&sr=8-5&ufe=app_do:amzn1.fos.17d9e15d-4e43-4581-b373-0e5c1a776d5d&th=1

SteamingatMohawk

Oops, I didn't format the horizontal axis correctly to show time. Ignore the time spans from 1660 to 1700, 1760 to 1800 because I goofed.

SteamingatMohawk

@jesmed1 There are 3 windows in the front and one radiator below the larger center window, not 3 radiators.