Troubleshooting long cold cycles (Honeywell TH8320R1003 VIsionpro)

boobird

I have an old brick house 3 floor in NJ. An old steam system with big supply/return pipes that was converted into gas hot water boiler (an old Slantfin 225K).
5 Cast iron radiators per floor x 3 floors. It is a 3 unit building with no zone valves..just 1 zone.

Problem:
The house gets too cold for long periods of time (hours).
Tenant complains that sometimes it is warm all day but turns off early at night. Then it turns back on at approximately 3AM (he was awake). Its not really on in the mornings around 6-8AM. Then back on around noon.

3am - heat turns on
6am - heat turns off
12pm heat turns on
5pm - heat turns off

He thinks its almost on a timer and turns on around the same time everyday.
Occasionally it gets too hot.

I have a Honeywell TH8320R1003 VisionPro with wireless sensors.
Thermostat Settings:

• Cycles/hour: 3
  
• Wake: 4am @ 74F
  
• Leave: 9AM @ 73F
  
• Return: 1PM @ 73F
  
• Sleep: 5PM @ 74F
  
• Application type: RESIDENTIAL
  
• Thermostat type: programmable
  
• HEATING system: Other
  
• primary heat stages: 1
  
• scheduled periods: 4
  
• adaptive recovery: no
  
• maximum heat setpoint: 82
  
• wired sensors on s terminals: no
  

Slantfin 225-GG Boiler:

• Aquastat was set to 190. Then 200. Now 210...(increased temp not helping)
  
• Water pressure @ 20 PSI
  
• The water temperature gauge appears to be broken! The needle doesn't move at all.
  
• #60 Expansion tank appears to be OK (taps hollow). It was replaced last year.
  
• The B&G circulator might be leaking oil? I saw some oil on the ground below it. I topped off with a healthy amount of oil and put some cardboard below it to see if oil was dripping from the circulator. The cardboard is clean so far...
  

The system is setup similar to the diagram on the right. Except I don't see an automatic air vent to the left of the expansion tank.

Cast Iron Radiators:

• There are 5 thermostatic radiator valves on the first floor only. The other floors do not have these valves.
  
• Bled the radiators by letting out around 2 cups of water per radiator, even if there was no air just to be "safe"...then I would go back to the basement after each radiator to refill the water pressure back up to 25 PSI. (it eventually falls down to 20 PSI)
  

boobird

The tenant says the radiators get cold and they have to use a space heater. I am flummoxed because I assume a 74/73 timed thermostat should keep pretty consistent heat.

STEVEusaPA

Where's the sensor? I would put the sensor in the living space, the vision pro in the basement, set it for one temp (permanent hold-no programming), and see how it performs.
Turn your aquastat down! It's too high, and you don't know what temperature it's reading.
Overall you are going to need someone to come in, and go over everything-the TRV's, boiler water/temp/pressure, make sure that aquastat can shut off at high limit.
You can also over oil the B&G and wreck it.

DZoro

How many wireless sensors do you have? One per floor? Changed batteries in them? Has the system ever functioned normal, were there any recent changes other than raising the water temp?

Fred

It basically is on a timer, that thermostat. It turns on at 3AM to bring the building temp up to 74 by 4AM, then it turns off at 6AM because the thermostat/remote is satisfied. It is then in that 1 degree set back by at 9AM so it won't come back on till noon to bring the temp back up a degree by 1PM. Set the tstat to hold 73 or 74 all the time and move the tstat and the sensor to a location that is more representative of the temps throughout the building or put the sensor in the coldest apartment. I bet you have them in the warmest locations.

ratio

Do you know if there are any other controls in the loop?

Also, be wary of "adding a healthy amount of oil" to the B&G pump. A common failure is breaking couplers due to a softening of the motor mounts caused by over oiling.

boobird

The thermostat is in the basement and is not using the thermostat as part of the temperature average. The sensors are all reading properly. I have one sensor per floor, but am only using the 1st floor sensor, which is in the warmest location in the building. But even the first floor person complains about it getting too cold. I deactivated the 2nd floor sensors from the average temperature because I thought the tenants were moving them into the fridge, etc. Sometimes the 2nd floor would read 60F while the 1st and 3rd floor was 74F.

The only other 'controls' in the loop are the thermostatic radiator valves on the 1st floor radiators.

Last night I set a permanent schedule of 74 using the 1st floor sensor only. The heat was not on at 1:30AM. The heat was on at 6AM.

How about this proposal:
- Use the 1st and 3rd floor sensors as the temperature average.
- Lower the aquastat to 200.
- Set a permanent 73 instead of using a schedule.

Fred

You aren't "averaging" anything if only one sensor is providing input and it's on the warmest floor, and probably in the warmest area of that floor. Put the 2nd and 3rd floor sensors in the mix and let them do the averaging. I'll bet that changes the situation. Let the TRV's control any warm rooms, once the three sensors are averaging.

boobird

I will average in 1 and 3 floor sensors.
I will lower the aquastat from 210 to 190-200.
I will set a permanent 73 with no schedule.

I hope my heating bill won't run wild. Last January it was $600/month.

Aquastat - Hi
What does lowering the aquastat from 210 to 190 accomplish?

Does the boiler turn off once it hits set temperature of 73?
OR
Does the boiler turn off once it hits the High aqustat temperature of 190?

Cycles/Hour CPH
How does the Honeywell cycles/hour factor into this? Originally the cph was set at 10, and it was on/off way too much. But I think the tenants were "happy". My goal was longer cycles. Do i need to increase cph from 3 to 4? The supply pipes in the basement are very big, like 3" diameter...so the system holds a lot of water...(not sure if that is relevant or not).

ratio

Lower cycles per hour = longer times, both on & off.

Why so high on the aquastat? Maybe some others will speak up on the temp, but it sounds notable to me.

Jamie Hall

Unless you are wildly under radiated -- which seems unlikely -- even 190 is pretty high for aquastat. Of course, if this is a converted steam system, you may indeed by wildly under radiated...

As to what turns the boiler off -- the aquastat. The thermostat should be controlling the circulating pump. Some installations the thermostat will also turn off the boiler.

Cycles per hour should be no more than 3 for your system.

boobird

@Jamie Hall @ratio @STEVEusaPA
The radiators wouldn't get very hot at 180. I tested 190 and 200. The radiators get hotter, but it doesn't seem to help with the long periods of cold cycles.

Aquastat vs Thermostat
Lower aquastat (180) + Higher thermostat (74)
vs
Higher aquastat (200) + Lower thermostat (73)

Is there a significant difference in comfort and/or heating bill?
Obviously lower aquastat (180) and lower thermostat (73) would be nice..

Warmest vs coldest sensor
warmest sensor (1st FL) + setting a higher thermostat (74)
vs
coldest sensor (3rd FL) + setting a lower thermostat (73)?

Is this inherently different as far as generating more even heat?

@Fred
>It basically is on a timer, that thermostat. It turns on at 3AM to bring the building temp up to 74 by 4AM

Well, I set Adaptive Intelligence: OFF. OFF means that there should be no ramp up time...according to the manual.


I dont think ramp time below applies to me since it seems to refer to "Commercial" and mine is set to "Residential"



HEATING system: Other
My B&G pump is only on when the boiler is on. Is this normal? Should the circulator pump be on even when the boiler is off (to circulate around any remaining residual hot water..?

ratio

It sounds like you have some kind of problem with water flow, if 180° water doesn't get the radiators hot. Do you have any way of getting the temperature of the water pipes, both heading towards the radiators & coming back from them?

Maybe a few pics of the piping around the boiler?

boobird

@ratio
Enjoy the mess that the previous owners left me..I know it is bad.

boobird

@ratio
When I touch the 3 return lines, they seem to be almost as hot as the supplies.

DZoro

You have plenty of valves there, throttle down a return valve and listen for flow in each return. Should be able to hear the water flow. You may have a pump / pumping issue.

ratio

The side of the boiler where the pump is too, please.

Have you tried the "Find a Contractor" button at the top of the page? It doesn't sound to me like you're going to be able to fix your issues by averaging the space temps.

boobird

@ratio

ratio

Are there any radiators that never get hot? When the system is heating, all of the radiators reach about the same temperature? That temperature (of the radiators themselves) is noticeably cooler than the pipes at the boiler, both supply and return? what is the height difference between the boiler & the highest radiator (±5' is good enough)?

boobird

@ratio
All the radiators get hot.
I "think" the 1st floor radiators get hotter (well, the rooms get hotter)...
I "think" the supply/return pipes are hotter than the radiators.

The highest radiator is about 25'-30' above the boiler.

ratio

Has this system ever worked? Are all the radiators identical? Can you add a pic of one or two, that shows the piping around them too?

A real temperature of the supply & return pipes close to the boiler, 5-10 mins into a heat cycle, is needed. A kitchen digital thermometer can be used, maybe with a piece of tape to bolt it down for a minute or so.

boobird

I just bought the property last year. Apparently the first floor would get too hot relative to floors 2 and 3. This is why I installed Thermostatic radiator valves on the first floor so they could reduce the heat.

The radiators are all identical (but some are bigger than others...)

What should be the proper temperatures of supply and return?

DZoro

Depending on the amount of radiation you have you should easily see 10 plus degree differential. Have you bled air out of all the radiators? Are you able to bleed air out of each individual rad? From the pics you have, system looks like you could easily zone each floor.....

boobird

I'm not sure if there is any air in the supply pipes, but I bled the radiators individually.

HVACNUT

There has to be a Heat Type setting for hot water, not "Other".
Also turn on the adaptive recovery.
Is the program set up for 5/2 or 7 days? Is the thermostat set for the correct time and day?
Are you positive it's a thermostat problem and not an intermittent boiler problem?

boobird

@HVACNUT
The Heat Type options are: Conv. Forced Air, Heat Pump, Radiant Heat, Other

The progam is turned off and I have it at 74 Permanent 24/7

It may not be a thermostat problem...

boobird

Does anyone have a guess as to whether this supply pipe layout would be restricting flow to one of the 3 loops?

DZoro

You could do some "poor mans" flow controlling by adjusting the valve to the hot floor, so that more flow goes to the others. Still think you have the perfect application for zone valve per floor...

boobird

@Dennis
I have some questions about zone valves.

If we split it up into 3 zone valves with taco circulators, each floor would require a thermostat that the tenant controls. Because I am the landlord paying for heat, I want to limit the max temperature in each unit's thermostat to 75.

One tenant stays home all day.
Two tenants works a normal job and is out during the day..

Lets assume the tenants setup some type of program where the thermostat is off during the day in 2 of the units...the energy savings would be significant..? Why do some heating guys tell me to keep the temperature permanent instead of using a program?

HVACNUT

I would contact Honeywell.
800-468-1502.
Specs on page 3 State applications for hot water.
This is not connected to a RedLink IEM right? No WiFi?
All 3 back up heat options are turned off?
Set for residential, not commercial?

boobird

@HVACNUT
No wifi or Redlink IEM
Connected to Wireless Indoor Sensors
backup heat = off
Set for residential

Oddly, I noticed 2 days ago that the thermostat reading dropped instantly from 74 to 66. I was reading from sensors 1 and 3. I assumed it was one of the tenants tampering with the sensor.

Both sensors seem to read good now.

DZoro

Yes you can have full control on many stats. You can set maximum and minimum heat settings. Many new stats have password codes to get into....

Fred

If you have tenants "messing around" with remote sensors, maybe because they are not satisfied with the overall temp in their unit, the averaging done by the tstat may well be the issue.

boobird

I may replace the wireless sensor with wired sensor.

I have also warned them that tampering with the sensors may actually shock the boiler and shutoff the system. (wink wink)

The concept of zone valves intrigue me. The big question I have is how much money it would actually save me if the 3 units were to run on programs.

Another question is whether its OK for the 225K BTU boiler to be running on/off trying to satisfy 3 programs. Each unit is 1000 sq ft.

Fred

Trying to zone each unit will make the boiler over-sized all the time, unless all three zones call for heat at the same time and the boiler is even properly sized to begin with. That's not the path you want to go down. The boiler will short cycle with virtually every call for heat by any one zone.

boobird

@Fred
That is exactly my concern...serving 1 zone with a large 225K boiler.

boobird

For my system, the circulator is ON only when the boiler is ON.

Is the circulator supposed to run some of the time even when the boiler is not running?

My gut says that circulating water thru the system will service more residual heat into the actual apartment. Otherwise, it seems the hot water would just stagnate in the supply pipes..

HVACNUT

> @boobird said:
> For my system, the circulator is ON only when the boiler is ON.

Do you mean, only when the burner is on? That depends on the type of aquastat. A high limit only aquastat will run the circ constantly on a heat demand and the burner will cycle off an on with the limit. Other aquastats will shut the circ(s) off when boiler temp drops below a certain set temperature, then start again once a differential is met.
>
> Is the circulator supposed to run some of the time even when the boiler is not running?

It can. On a high mass boiler, a heat demand can sometimes be satisfied without the burner ever coming on.

Did you contact Honeywell?

nicholas bonham-carter

Maybe there are leftover orifices in the rads from its days as a vapor system.
Set up the temperature of the TRV’s, and cross the wires of the thermostat, to make the system run constantly, and measure the surface temperatures of the rads after an hour or so to see if there are any restrictions in the flow.—NBC

boobird

@HVACNUT
A high limit only aquastat will run the circ constantly on a heat demand and the burner will cycle off an on with the limit.

I have a high limit only aquastat. My boiler & circulator will run on a call for heat. However, the circulator never seems to run when the burner is in an off cycle. The circulator only runs if the boiler is on. (I think).

Is this a bad thing?

HVACNUT

If its truly a high limit only aquastat, then its not correct. Circ wiring goes into the aquastat, connected to C1,C2?
Can you post a pic of the aquastat?