Changing out old fin-tube baseboards and conventional boiler for new Runtal panel rads and a mod-con boiler. I'm shooting for 150 degree water, but will set a limit of 180 degrees. I'm agonizing over which type of PEX to use. I'm leaning toward the Uponor HePEX because I think it has a superior connection, but several contractors have recommended PEX-Al-PEX citing high heat and movement/noise. Has anyone used HePEX for repiping radiators? Are you happy? Opinions?
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JG plumbing
Well-Known Member
I would say pex al pex is a step up in quality, but it can delaminate. I also don't like the fitting system or pex al pex.
I would use hepex.
I would use hepex.
JG plumbing
Well-Known Member
No I meant what I said. These are trade off's.
JG plumbing
Well-Known Member
When pex al pex delaminates it still works. It's just something that can happen.
JG plumbing
Well-Known Member
The hepex obviously doesn't have the layer of metal pipe for protection which makes it a step down, but it can be run more true to size since it expands around the fitting rather than the fitting being smaller in size to fit the pipe. That said if your replacing metal pipe make sure your calculations are for pex sizing.
Thanks! Sizing IS my next question to tackle.....
I re-read Siegenthalers Modern Hydronics book...several times over and still get totally confused. For the most part, I'm going to use, as he suggests, 1/2" PEX from the Manifolds to the radiators as home-runs. The house is 60' long (old ranch) and the boiler is on one end...it is a long run to the bedroom radiators and would prefer not to run a bunch (10 ea) of 1/2" PEX the entire distance. So, I'm thinking about using 1" straight Uponor pipe from the primary boiler loop out to my bedroom area (3BR) and baths (2), to a supply/return manifold attached to the bottom of the joists in the basement bulkhead, then run 1/2" to the rads with TRVs from there. If I use a variable speed/pressure pump do you think that will be OK? Anything I should think about?
I re-read Siegenthalers Modern Hydronics book...several times over and still get totally confused. For the most part, I'm going to use, as he suggests, 1/2" PEX from the Manifolds to the radiators as home-runs. The house is 60' long (old ranch) and the boiler is on one end...it is a long run to the bedroom radiators and would prefer not to run a bunch (10 ea) of 1/2" PEX the entire distance. So, I'm thinking about using 1" straight Uponor pipe from the primary boiler loop out to my bedroom area (3BR) and baths (2), to a supply/return manifold attached to the bottom of the joists in the basement bulkhead, then run 1/2" to the rads with TRVs from there. If I use a variable speed/pressure pump do you think that will be OK? Anything I should think about?
JG plumbing
Well-Known Member
Remote maifold is a good /common solution to what you have. Just have a good way to purge your system of air and balance the loops. If you have that book and are following the guidelines you should be good.
1"pex can run something like 70k btu's (going from memory) . It just depends of your load. Have you done a fresh heat loss Calc?
1"pex can run something like 70k btu's (going from memory) . It just depends of your load. Have you done a fresh heat loss Calc?
Yes, I had a pro come in to do it, but don't trust the result. It was an order of magnitude lower (50K) than several back of the napkin estimates. His calc was about the number of BTUs in here now and it is cold in the house. Some of the assumed values, regarding the current construction weren't realistic. At one time there were radiators in the basement, but the previous owner removed them (copper through slab). I'm putting heat (panels) throughout, including the basement. I attempted to get the largest radiators I could put under each window in order to run the lowest water temps possible. Guess I won't really know if I'm close until the magic happens. I'm about 80K BTU in output when it is running at 160 degrees.
JG plumbing
Well-Known Member
The way I was taught to do heat loss Calcs are pretty accurate. If he went off of what your have now I wouldn't be confident. You can use the slant fin app. It's tedious and you have to be sure your inputting the info correctly. But it is accurate.
Thanks! I saw someone reference that previously, but haven't downloaded it. Will do! My basement is totally open and has been that way for a long time. I need to get it done. Very few houses like this still exist and even fewer have hydronics. The contractors who do this are into small commercial work or radiant in floor for high end homes.
JG plumbing
Well-Known Member
It is by far the most effeciant and most comfortable way to heat. Its complex which takes most installers away from it and it's expensive to install which takes the customers out of it.
If i had the money and a blank slate I would run duct work in the ceiling or attic for ac and hydronic for heat. Then have a warm air furnace for back up. Gas fired.
If i had the money and a blank slate I would run duct work in the ceiling or attic for ac and hydronic for heat. Then have a warm air furnace for back up. Gas fired.
J, I'm trying to determine how the manifolds will be arranged. I have a workable plan for the main/upstairs, but still trying to figure out how to control and pump the basement. I have a common area in the basement and a couple of other TRVs, one in a laundry and one in the bathroom. I plan to have 3 large rads in a common area, approximately 20K BTU on a central thermostat. So the controls would be 2 TRVs and the remainder controlled by actuators to a central thermostat. I would like to use a variable speed pump to a single manifold to balance the circuits as the central thermostat or TRVs are adjusted. Do you think this will work?
JG plumbing
Well-Known Member
I tend to think in sketches. Do you mean zone valves when you say actuators?
Not quite following the specifics. Your saying the thermostat will start the boiler and the pump for those three radiators then your using thermostatic radiator valves to control two of them leaving one to run full bore?
Not quite following the specifics. Your saying the thermostat will start the boiler and the pump for those three radiators then your using thermostatic radiator valves to control two of them leaving one to run full bore?
arctic bill
Well-Known Member
In Canada Uponor will not sell to anyone who is not a fully licensed plumber and has taken their course on proper insulation. also any job is guaranteed for 25 years parts and labour. Now that is what i am talking about . what is it like in the usa.
JG plumbing
Well-Known Member
I get what your saying but there are a lot of specific things to differentiate. You said valves plural. Is this one zone with three radiators and one pump?Yes, zone valves at the manifold for 3 radiators in the recreation room/common area of the basement. Then I would prefer to have the thermostatic valves on the radiators (TRVs) in the bath and laundry.
This is why a sketch is the best way to communicate with these.
JG plumbing
Well-Known Member
Most real suppliers here will only sell or communicate with plumbers /hvac guys. The boiler manufacturers are the same. But anyone can go to a big box store and get a lot of the stuff to do this type of work. They won't get much support and it usually gets messed up, but it's a free for all deal if someone is motivated.In Canada Uponor will not sell to anyone who is not a fully licensed plumber and has taken their course on proper insulation. also any job is guaranteed for 25 years parts and labour. Now that is what i am talking about . what is it like in the usa.
arctic bill
Well-Known Member
other manufactures of pipe like pex do the same but Canada Uponor will sell only to contractors that have taken their course. I love em . I remember when poly b came out every tom dick and harry was slapping in the stuff like crazy. then the stuff started to fail . go figure.Most real suppliers here will only sell or communicate with plumbers /hvac guys. The boiler manufacturers are the same. But anyone can go to a big box store and get a lot of the stuff to do this type of work. They won't get much support and it usually gets messed up, but it's a free for all deal if someone is motivated.
I get what your saying but there are a lot of specific things to differentiate. You said valves plural. Is this one zone with three radiators and one pump?
This is why a sketch is the best way to communicate with these.
Yes, appreciate your help. Here's a sketch of the house that I used to plan the radiator install so you have the terrain. The plan as it is now, is to put a small tank on the boiler to deal with the individual rooms that will be on TRVs so that problem should be solved. I will run a 1" pipe from a manifold near the Bedroom group back to the boiler distro panel.
BTW, a contractor will install the pipe and they have the training from Uponor, but these guys don't have experience in 'planning' a hydronic system such as this. I've been to over a dozen HVAC reps over the past year and couldn't find a single one.
This is why a sketch is the best way to communicate with these.
Yes, appreciate your help. Here's a sketch of the house that I used to plan the radiator install so you have the terrain. The plan as it is now, is to put a small tank on the boiler to deal with the individual rooms that will be on TRVs so that problem should be solved. I will run a 1" pipe from a manifold near the Bedroom group back to the boiler distro panel.
BTW, a contractor will install the pipe and they have the training from Uponor, but these guys don't have experience in 'planning' a hydronic system such as this. I've been to over a dozen HVAC reps over the past year and couldn't find a single one.
