Not getting enough heat - hot water radiators

josieT

I have a new hot water heating system for an old house. The heat can barely get above 64 even with 34 degrees outside. I definitely have a window issue as I have single pane metal frame windows. I plan to install interior storms to address that. But right now, I'm not concerned with efficiency. I just want to get the house to 75 even if I have to burn more energy. I assume bad windows just mean the boiler works harder.

My max boiler setting is 180. There is an outdoor reset control. The boiler temp is running around 150-160 degrees F with the outside temp around 30-35 degrees. When the boiler ran at 197 (before I had the setting changed) it was a few degrees warmer. But 197 is too high to run the boiler on a 30 degree day.

The radiators are hot ( but still can be touched for a few seconds). Using an infrared thermometer, the radiator emitted air is about 140 degrees near where the openings are. Steady hot air is coming out. The water temp of the pex near the entry of the radiator is 100. So I assume the radiator helps increase the air temperature? I have bled the radiators at least twice in the last month. So it's not air bleeding issue.

Also there are 6 zones. The zone with the most radiators is set up as a continuous flow with first radiator putting out air at 144 degrees, dropping to 134 and then 125 on the last one. Are these drops normal?

I don't think the boiler is undersized at an Ibr rating of 96k. Home is 2000 sq feet with 6 zones. But I only have 2 zones cranked up to 75. No other appliances running.

I thought the radiators might be undersized but the water temp of 100 is not at capacity.

The infrared thermometer may be less than exact. But can I assume that if the water thermometer near the boiler is saying 150, then the water into the radiator should be 150?

The water temp coming out of the thermostats at the boiler point is 110. I would expect that if the rooms are not at the thermostat setting, then the system would deliver 150 degree water temp to the radiators.

In the pictures, there is a set of thermostats on the right for the radiant floor. ( that's a whole other animal, ignore that for now). I'm just trying to figure out the second floor that uses the radiators. Again I assume the temp for that can get to 150 and is not affected by lower water temp needed for the floors.

I've had such a terrible time with contractors, that I realized I must get informed before anyone else assumes I'm ignorant and wants to rip me off. So any guidance before I get a plumber to come out would be very appreciated.

Josie

Jamie Hall

The easy stuff first... an IR thermometer reading off PEX will not give you an accurate reading. You might have better luck reading wrapping (tightly) black tape around the PEX and reading off of that.

You note one set of radiators piped in series is giving a significantly higher temperature on the first than the second than the last. That is significant (it's also "normal" -- but not really right). What it means is that you don't have enough flow.

In fact, my guess without more information is that that is your entire problem: not enough flow. What pumps do you have? Can you draw a diagram showing the pumps and valves?

Tinman

I thought this looked familiar. JosieT, were any of the concerns and suggestions from back in November addressed?

GW

Josie, 75 is not a realistic goal for a residential heating system. Anyway, seems like you may have other problems. There are a few variables not mentioned.

Are you sure it's a heating system problem? Window issues can lose lots of heat. Did your past sysyem heat the house properly? How many zones did you have originally?

I would not bet my coffee money on your IR temp gun readings. Plastic piping will yield less than accurate readings. Most pros use a k couple contact thermometer

Your zones can add to this issue, you running only 2 of the zones as you describe this problem? Do you see how this can affect your explanation?

Just because you have water does not mean you don't have an air issue, it's hard to explain.

Gary

josieT

Thanks for the reply and time Jamie. I will do a drawing and post tomorrow. I'm a layman but I think I can figure it out what to draw. It's a grundfos pump. The pressure is showing 15psi which I thought was normal. Stupid question - is pressure indicative of flow?

Jamie Hall

Pressure really isn't indicative of flow directly; in a system such as yours, that pressure might be a little low but is probably OK. I will wait for the diagram for further commen, though I have some suspicions.

Where is this located?

josieT

Stephen, yes. A lot of changes were made. We scrapped the radiant floor in the sunroom and changed it to baseboard to keep it simple. So no issues with the pex runs on the concrete slab and insulation layer. Gas piping was changed. A few other adjustments were made.

josieT

Gary, unfortunately I have no baseline. It's my first winter in the home. It used to be steam. I know the windows have to be addressed. The heat loss is terrible through the windows. I am going to get interior storm windows as I can't afford replacements. Appreciate the feedback on the IR readings. I've been running around like a maniac checking temps.

I thought that while windows are making my system highly inefficient, that I should be able to attain the desired temperature with perhaps the boiler just running more.

Josie

Jamie Hall

Oh dear. Josie, I see a huge red flag.

"It used to be steam".

Are you using the same radiators as were used for the steam system? Do you know? Because if so you may be seriously under-radiated. A radiator produces only about half to two thirds as much heat when used with hot water as it did with steam.

Since the steam was scrapped -- in my humble opinion. a HUGE mistake, your only hope may be to radically improve the windows and add a lot of building insulation, or to add a lot more radiation.

You need a complete heat loss done on this structure to find out where you stand.

josieT

Thanks Jamie. Yup. I know I made a huge error. I beat myself up on this a million times. Trust me. I wish I had come to this forum last summer. This my my first home and first time dealing with contractors. Now, all I can do is try to get myself educated and get the problem solved and not get screwed again! Very tiring and frustrating experience.

On the radiators - it's not the same radiators. There used to be convectors. the second floor has recessed sunrad type cast irons. There were heat loss calculations done to size these. The radiator company (OCS) did the sizing of the radiators, not the plumbing contractor. I did my own calculations too but the calculators out there vary so wildly. The radiators did fit into the existing wall recessions where the convectors once were. I assume these radiators would give off more heat than convectors. My thought though is that the water temp in the radiators isn't high enough so at this point I don't think they are undersized. First floor is radiant floor.

On the windows, given this is a Tudor, the windows are old metal type. It's not a simple thing to replace cost wise. Hence looking at interior storms.

I tried to draw the boiler configuration out but it's out of my domain of expertise. I attached a few more pictures including the 2 pumps.

I will obviously need to find a good person to resolve this. But it's very hard when you're not an expert to know who to believe. Hence I'm trying to make sure I don't get taken advantage of again.

Josie

GW

Josie, I'm sorry you're learning the expensive way. We are all consumers, we all have been jammed- some worse than others of course.

I would vote for reducing the heat losses- this investment would reduce your fuel costs for every winter to come.

Heat loss calcs: this is an small art form, not rocket science but there are some ins and out to know when to add and subtract to the calcs. Infiltration is the biggest unknown unless you've had a blower door test done.

I hope you can get this resolved soon.

Gary

rosio

x

GW

Josie, each rad has its own set of pex lines? If YES, your plumber is incorrect. We routinely pipe rads with 3/8" pex, big one, like 8000 BTU. The pex rep says he has seen 10,000 work (if runs are not too long) with 3/8"

If NO, then you may have an issue. Does each rad have its own set of pex lines?

YES, you can temporarily seal up your windows, hardware stores have that shrink film stuff; I would recommend doing that. Taping pillows---I have never seen that done, but sure, the more insulation the better. It's the air that is killing you (air leakage)...Pillows may not stop the air. You need to buy that shrink wrap plastic to seal the air.

You may have covered this- you have radiant? Is that what the mix valve is for?

Gary

KC_Jones

Pillows in all likelihood would be way beyond what a new window would do. For an experiment you could try some of that plastic that gets installed on the interior trim and you use a hair dryer to shrink it into place. The biggest problem with old windows is air infiltration not insulating value. Even the best modern window is a huge hole in your insulation, they just don't let as much air in because they have superior weather stripping. Even the best modern windows have an R rating around 3 and a single pane is around .9 or so. Standard wall insulation is R-15 so like I said still a huge hole in the insulation...it's about the cold air.

josieT

Here's the set up. On floor 2, there are 3 zones of cast iron (recessed rads). Zone 1: Son's bedroom, main bathroom, and daughter's bedroom. Zone 2: master bedroom and bathroom. Zone 3: Garage and 4th bedroom.

Zone 1- I observed that pex goes from the boiler to son's bedroom. Return pex goes back to basement and then connects to daughter's bedroom. That return pex goes to the bathroom. Return from the bathroom goes back to the boiler. My daughter's bedroom has a copper line from the pex in the basement to the bedroom because that line is used to heat the lower bathroom (not well).

The looping (I think this is called continuous flow) I assume is why the radiators have 10 degree drops between each room. The master I assume is similar. The 3rd zone is cast iron baseboard in the garage going to radiator to the 4th bedroom.

so each rad has it's own pex lines but the pex for some of the room is in that continuous loop. But even the first room in the loop, the heat isn't great.

The first floor is radiant floor which is why there's the mixing valve. There's also a sunroom with baseboard on it's own zone.

Jamie Hall

Besides the shrink wrap on the windows (I use it; great stuff) you may actually have a little luck here...

You mention that in Zone 1 the PEX (I do hope it's barrier PEX...) goes to a radiator, then back to the basement, then to another radiator, then back to the basement, then to another radiator. I can't think why it was done that way... but that is a series loop. It might not be all that difficult to repipe just in the basement, so that all three radiators got their feed directly from the source, and then came back to a single return. That way all three radiators will get hotter water. You may find that you may need a bigger pump...

I still don't know where you are located. It is quite possible that there is someone near enough whom we can recommend.

Harvey Ramer

There is still a problem with your near boiler piping.

The problem is with the mixing valve and pump location. Depending what type of valve it is, it may be allowing hot supply water into the return piping by the boiler. This would prevent the boiler from firing at max capacity and also reduce the flow rate going out to the radiators.

Here's how to check it. Turn up every thermostat in the house so all zone come on. Wait 10 minutes. Now see which pipe is hotter, the pipe that supplies return water to the cold side of the mix valve or the vertical main return right after all the branches are tied in.

Ironman

Harvey's right. The pump has to draw through the "MIX" port of the mixing valve. It's not piped correctly.

Zoning up a mod/con boiler like that is a bad design. It will cause short cycling which will greatly reduce the boiler's life and efficiency.

josieT

Jamie, I believe what you're describing is the monoflow set up with venturi Tees? I'm glad this may be doable. From what I see in the piping, it doesn't look too hard to do.

There are a number of elbow joint in the pex running from the boiler to the rads. Is this normal?

I sent you a private note. If you know of any local contractors that you can recommend, please let me know.

Josie

josieT

Thanks Harvey. Honestly I didnt feel any noticeable difference in the different points of the mixing valve. I was expecting one side to be cold but all sides were warm. Does cold side mean cold or even lukewarm? is there an accurate way to measure this?

A few other things I have been told that would be great to confirm. I was told the pump was in the wrong place. Something about it needing to be on the left. My plumber added a second pump so not sure if this addressed that. Another comment is that an air separator is needed.

Josie

josieT

Ironman, The boiler is constantly on. I'm in no way an expert in this.. but it seems to always be running. My electricity bill went up $50 a month once the boiler was installed. Is this what you mean by short cycling?

Ironman

No. A short time on, a short time off, etc, etc, etc.

Rich_49

Josie , Those recessed rads also have a 10% efficiency hit because they are in the wall .

josieT

That's a good point Rich. This has been so overwhelming to deal with especially with a new baby last year. I just need to get to a solution. Any opinions would be appreciated. I see these options:

1) first hole up the windows with as much insulation and tape, weatherstripping etc so it can at least how much of the issue is windows. If it is windows, figure out if interior storms or replacements are the way to go
2) since the current system has flaws like pump location, get the licensed plumber who signed off on this to fix those specific issues with the boiler. Also try the moonflow suggestion from Jamie. see if this fixes the problem. If not:

3) scrap the radiant floor and/or install panel rads on the first floor
4) scrap the radiators on the second floor (we tried to widen the recessions but they were maxed out everywhere but the 2 bathrooms). Put in panel rads instead
5) keep what I have and try to supplement with ductless heat from a mini-split

This is such an utter disaster. Probably will need to get a loan or sell the house at this point. But I'm in a hole so need to calmly work through a solution.

Again, any advice would be appreciated. I'm living with family members now but need to move soon. Lots of plumbing and heating people where I live, but it's hard to know who to trust.

Josie

Harvey Ramer

Josie, where are you located? If we could only get someone out there. Things may not be as much of a disaster as you think.

Rich_49

Harvey beat me to it . Please give us a location . As far as Monoflo system , don't do it . There are much better , far more efficient ways that are less time consuming . I would suggest a manifold with each rad having it's own supply and return , well placed bypasses and constant circulation . There are alot of fine heating contractors here . Maybe use the locate a contractor feature or there are some who travel .

GW

Josie said: Lots of plumbing and heating people where I live, but it's hard to know who to trust.

Trust......I think you may mix up trust with expertise. It's most often not about trust as it is knowledge/experience. Most contractors are good hard working people not purposely trying to scam you (of course those people exist too). It's just their lack of knowledge.

icesailor

"" Josie, each rad has its own set of pex lines? If YES, your plumber is incorrect. We routinely pipe rads with 3/8" pex, big one, like 8000 BTU. The pex rep says he has seen 10,000 work (if runs are not too long) with 3/8" ""

I've re-read this string. For the sake of discussion, you all are right, I'm wrong.

"The PEX Rep says". The PEX rep doesn't know squat and has never run a foot of PEX. Back when we did what we were told by the old dead guys, no one ever ran less than 1/2" ID copper to a second floor Sunrad and often, it was 3/4" ID copper. Because of the overall length of the loop too and from the main. We never saw series looped radiators. You just didn't do it.

Way back when, IBR/Hydronics Institute taught THOUSANDS of "heaters" how to calculate and install hydronic systems. In a 2 day course. They all worked. When you see an old system in operation, it worked and had its basis in IBR training. Somewhere, during the last 30 years. the training lost favor and was dropped. You could buy the courses and teach yourself. The one thing you really learned was about the lengths of circuits and how too small piping and restriction killed delivery.

Without double checking, cabinet convectors didn't give off as much heat as a Sunrad cast iron radiator. Not one here has mentioned that the "new" Sunrad needs a piece of a minimum of 1/2" reflective urethane foam board behind the radiator against the outside sheathing. Its possible that 1/2 the output is being lost through the wall to the outside.

3/8" PEX? If the 3/8" PEX is ID, there is no way to get enough hot water through a long length of 3/8 ID PEX to get the listed output out of that radiator.

I'll get back to flying.

I read an article by someone who was the publisher/editor of some flying magazine. He had been flying for many years. He got a call from his first instructor who had a FBO in North Carolina who asked him to come and visit. While there, the FBO guy had an aircraft he had serviced and it needed a check ride. He asked the editor to ride along. Some simple single engine fixed prop low wing thing like a Piper Arrow. Big fat wing, and slow. The editor took the controls and tried to fly it. He almost crashed it. A pilot flying the latest aircraft out there from turbo twins to jets. Almost crashed the easiest student aircraft out there. The editor went home and pondered on his dilemma. He realized that he had forgotten the basics of flying. He was so used to flying hot airplanes that took a lot of skill to fly and had all kinds of things to help, that he forgot the basics of flying. He called up his old instructor friend, the FBO and made arrangements to come down for a month and learn how to fly again.

Too many of the problems I see reported here are caused by installers not knowing the basics, and some of us here forget the basics of what we know in favor of all the latest ideas. When the solution is as basic as turning the key on to start the engine.

Maybe I am backwards, or I learned backwards. First, I saw all the old systems that worked. Then, I installed systems like the old ones that worked. Then, I learned how they were supposed to be designed for optimum performance but still followed the old rules. Now , we have new rules? The issue is this SU'ed heating system. Moving the circulator to one side of the boiler to the other will not resolve one thing that will make the building any warmer. There are far deeper problems here. Someone didn't know their basics, someone had no training, and someone screwed up big time.

I gave up trying to do new installations in new houses. Someone knew far more than I. Some Contractor or homeowner bought a design and material from an Internet seller and delivered it to their door with plans. All you needed was for someone to put it together. I'll pass.

I made more money and learned more by figuring out why it didn't work and how to fix it. If it could be fixed. And many couldn't be economically fixed. 40* Delta T's? The only time I ever saw any 40* delta t's is when someone should have run four 200" of 1/2" ID radiant tube in a slab for a total of 800' but ran one 800' length. 5 days later, the water was still coming back cold, but a corner of the slab was warm. Bigger pumps caused more cavitation.

Hire professionals that know what they are doing. And understand and use their basic knowledge on a daily basis.

Jamie Hall

Josie -- I sent you a private reply on contractors. Did you get it?

GW

Ice man, I'm sure you're a very knowledgeable tradesman, 3/8 is very common these days. This system pictured has about 70,000 btu, worth of panel rads, all 3/8, all running perfectly well, making the 100,000 work hard when we start it up from a cold start, (this is a contstat circ system, normally never a cold start). My rep used to live in the trenches, he knows his stuff.

Gary

GW

OK I lost the pic, anyway, what I mentioned is sound info

SWEI

If you do like they do in the EU -- and run your radiators at a 30°F ΔT -- 3/8" PEX can deliver 18,000 BTU/hr.

We oversize our piping here a lot, which I suspect may be contributing to those mysterious air elimination problems we see reported of late.

josieT

I'm in Long Island, Nassau County. Please pass me any recommendations. I would be grateful. Note, I had a gentleman come in from one of the professional radiant heating orgs. He charged me a lot of money for a consult including for his commute time 30 minutes away. Basically he pointed out the same things you guys did on this forum (pump location, air separator, etc). When he left,he took the money and apologized if he ruined my weekend. I didn't think the attitude was necessary.

Jamie, I actually had called both those contractors before the job started. They were really nice but do more commercial buildings and apartments. So they weren't willing to come out to give an estimate. They both said that they only run copper up and never use pex for vertical runs saying it's not as good as copper. There's the rodent issue but they also said pex was not as good for vertical runs.

The comment on the contractors is right. I didn't have anyone who was underhanded or unethical in any of my situations. These were all nice people and let me ask questions which I appreciated. Even the guy who put in this heating system kept chugging away at it and never asked for the balance of what I owed. The issue is ignorance and experience.

Iceman's comment: "Not one here has mentioned that the "new" Sunrad needs a piece of a minimum of 1/2" reflective urethane foam board behind the radiator against the outside sheathing. Its possible that 1/2 the output is being lost through the wall to the outside. "

Darn.. we didn't do this! Really 1/2 output lost? Those things are heavy and already piped. Not sure we can get the foam board back there. I actually went to OCS industries in Brooklyn and with my husband picked up the radiators and worked with them on sizing. They didn't mention the foam board. But sounds like a good idea. Will have to see.

Josie

icesailor

GW said:

Ice man, I'm sure you're a very knowledgeable tradesman, 3/8 is very common these days. This system pictured has about 70,000 btu, worth of panel rads, all 3/8, all running perfectly well, making the 100,000 work hard when we start it up from a cold start, (this is a contstat circ system, normally never a cold start). My rep used to live in the trenches, he knows his stuff.



Gary

Gary: I respect everything you do and say.

All I can say is that we used to have a rule. I carried a copy of it around in my wallet until it fell apart. It was basically that you could put 15,000 BTU's on a 1/2" line. 35,000 BTU's on a 3/4" line, and 65,000 on a 1" line. If I needed more than 65,000 I went to 1 1/4. So, I guess that 15,000 BTU's is equal to 1.5 GPM. Or 750# of water in an hour. Can you get 750# of water in an hour out of a 3/8" ID pipe, 100' long?

The electrical code has upsized their wire sizes to carry more load. We're downsizing to carry more load.

The best thing about PEX is that no one is going out and cutting it out for scrap to sell so they can but their dope. Like they do with Copper.

Rich_49

last time I checked there was no air elimination issues in an electrical wire

icesailor

That's true, but if you turn on a light and the other lights get dim, the wire in the circuit may be too small.

Rich_49

Maybe electricians should have more knowledge of what they are moving , you know like us . Most electricians do not posses th level of know;ledge that we have and just pull wire . We regularly do things that are well beyond code where they just meet code . We know that code is the very worst job we can install without some inspector having to fail us . They think code is the best job they can do .
We size our systems so that when all is calling no other circuit suffers and we can seemlessly deliver comfort . They obviously have not perfected that level of design capability .

SWEI

Rich said:

Maybe electricians should have more knowledge of what they are moving , you know like us . Most electricians do not posses the level of know;ledge that we have and just pull wire . We regularly do things that are well beyond code where they just meet code . We know that code is the very worst job we can install without some inspector having to fail us . They think code is the best job they can do .
We size our systems so that when all is calling no other circuit suffers and we can seamlessly deliver comfort . They obviously have not perfected that level of design capability .

You're hanging out with the wrong electricians.

Rich_49

Too many hacks in every trade I guess Kurt . Really wish it was not like that .

GW

Ice, yes, some rules are meant to be broken i guess (or updated)

Gary

josieT

Rich - You're statement on "I would suggest a manifold with each rad having it's own supply and return , well placed bypasses and constant circulation . "
- Is there a picture of this? I thought that the lines coming out of the manifold are controlled by a thermostat. So each line going to and from the radiator has to be one zone.
- Will this clutter the manifold?