Questions

BruceL · May 18

I have questions about rerouting some low pipes. Also I have a radiator that does not get hot. I got an estimate that said the radiator is clogged. I replaced a few radiators with pex. These work great, and have for awhile. I'm wondering if I can use the same pipe to reroute the low pipes.? I will post some pictures.

Jamie Hall · May 18

This appears to be a hot water heating system? The boiler trim, at least, suggests that… but it would help to know for sure. There are some aspects in the pictures which suggest possibly steam, or maybe it was a gravity hot water (not pumped).

I am puzzled by the comment "replaced some radiators with PEX". Eh? Do you mean yo took a radiator out and put a PEX pipe in in between what was the inlet and the outlet, or what?

If it is steam, there are some low pipes, called wet returns, which could potentially be safe with PEX. Otherwise, I'd not use PEX, as its working temperature limit is below the safety limits on a hot water boiler, never mind the working temperature of a steam boiler.

But let's know a little more about the system…

hot_rod · May 18

How many radiators do you have? About how many square feet are you heating? That seems like a fairly large boiler.

If you need the full btu capacity you would need to repipe with 1-1/4" pipe, around a 14 gpm flow.

Seems odd for a radiator with those size connections to get plugged??

That boiler may not be vented properly, is it a power vent model.

BruceL · May 18

Yes hot water system. Yes I put pex in between the inlet and outlet of the new radiators. So one of my questions is can I reroute the low gravity system pipes with 1 inch pex. Also is it still a gravity system with the boiler pump?

BruceL · May 18

The house was built in 1930. It had the original boiler when I moved in. I think it was origially coal converted to gas . total gravity system.

BruceL · May 18

So I thought the working temperature was 180 degrees and my temperature never gets above 145.

BruceL · May 18

180 degrees for the pex. It was suggested by my original boiler advisor. I did hear the guy who sold it to me say something like that. Advice has been hard to come by. And estimates have been so high. Anyway its been working for many years. So easy to work with

BruceL · May 18

The house is about 3000 square feet. 5 large radiators 3 smaller ones.

BruceL · May 18

I have definitely wondered about the venting . It has been working since 2009 when I installed it. It is a class b that goes through the chimney in a sleeve that a I got from standard plumbing gas department.

Jamie Hall · May 18

First things first. PEX is rated to 180 F. True. What positive safety cutoff is on your boiler which shuts it down — independent of anything else — before it gets to 180, in the event the aquastat fails?

Now it is no longer a gravity system, now that it has a pump.

mattmia2 · May 18

https://forum.heatinghelp.com/discussion/comment/1896813#Comment_1896813

the working temp is at the typical aquastat settign of a hot water boiler. If you look at the specs it is a curve of pressue and temp, at 30psig it can hold a lot more than 180f water.

GGross · May 18

directly connected flexible chimney liner right to the boiler?

hot_rod · May 18

The boiler operating temperature may be set at a typical 180°

But that doesn't mean the boiler will always reach that temperature.

If it satisfies the thermostat before it reaches 180, it may never run above a 145 or whatever supply or boiler temperature.

It is always the connected piping, volume of water and mass of the radiators that drives the boilers actual operating condition.

IF you runs most of them time at or below 145° that may cause condensing in the boiler and/ or flue piping.

It would be good to monitor that a few times throughout the season. Ideally on a design, coldest day the boiler would run nears its setting and stay there. That indicates the boiler and radiation is sized close to the homes design load.

If I had to guess I would say the home is under 100,000 btu/hr load at design, maybe even as low as 60,000.

A heat load calc would be good info to have. That boiler could be twice the size required?

BruceL · May 18

The house is a brick uninsulated very leaky house. I have improved it greatly with better windows and blown in insulation. The resting pressure is 12psi and working hard psi is18. I think he said the temperature was set to 145 and he could adjust it if the house wasn't getting warm enough. Its a one floor home. 1 zone. I replaced the original boiler with the current one myself. The estimates to replace it with asbestos abatement were unbelievable. I got the same boiler specialist to advise me for a small fee. They said the boiler was a good fit. Anyway I installed it in 2009 and it has been working well. The advisor from the plumbing company retired and I haven't been able to ask questions. He was the one who suggested the pex for radiator installation. This winter i found that a radiator in a bathroom not getting hot. I tried free estimate from a local specialist. He said it was clogged offered $$ $ power flush. Then I showed him the low pipes and he said he could reroute them for $$$. I really don't want to invest heavily in this technology. But I know I can buy a replacement cast iron radiator for under 400$. How can he be certain its clogged. He said his company could mega clamp for rerouting the pipes. I saw some other aluminum clad pex like pipe on this old house. Could I reroute the pipes going through the room without re piping the whole system.

HVACNUT · May 18

The perimeter piping looks like 2 inch. If @BruceL reduces it to 1 inch just in that location, won't there be flow issues?

Jamie Hall · May 18

A clogged radiator is almost unheard of. More likely airbound…

mattmia2 · May 18

it would be fairly easy for someone with basic pipefitting skills to break that piping back to a threaded connection and use a male adapter to replace with with probably a combination of copper and pex. pex in a large enough size for those mains would be expensive and unwieldy but it would be great for the runouts to the radiators.

please edit to remove prices, we can't talk about the prices of services

you wouldn't need the full size of the current main but it would have to be somewhere between probably 1" and 1.5" depending on what load is served by that section of the main.

EBEBRATT-Ed · May 18

A CLOGGED RADIATOR is a quote from someone who gives you a high ball price and doesn't have a CLUE what is wrong with your system.

Radiators especially Hot Water CI radiators don't plug.

Keep your eye on that pex over time it may get brittle

mattmia2 · May 18

insulate or paint the pex if it is someplace where it will be exposed to sunlight(or fluorescent lights), uv will degrade it

hot_rod · 12:04AM

If you have upgraded the building shell, that boiler is almost guaranteed to be too large. But you own it, so.

Good chance the entire home could be heated with 1" pex runs replacing those steel pipes.

Another option is a home run with 1/2" pex to each radiator from a manifold at the boiler. Then you have individual control and a system you could install yourself

You could have manual, or thermostatic valves at each radiator for unlimited zoning and tem perature control.

This happens to show steel panel radiators, it could be any type of heat emitter connected.

Aluminum pex is a good option.

Slide 3 is how Bob cleans up the pex home runs in the basement, running through pvc sleeves. A mod con boiler as show is a gret match for it's modulation and low temperature efficiency.

BruceL · 12:11AM

The pex leaks or doesn't leak. Its a lot cheaper then the alternatives. I had 2 leaky radiators. Again I could not work with local plumbers. I ordered and installed them. The whole system is so outdated for my area. I live in Salt Lake City and there are residential homes with boilers but not many. So finding plumbers with the right experience to ask has been very difficult.

BruceL · 12:13AM

Does anyone know how to troubleshoot a cold radiator. I traced the pipes back to where they get warm from underneat in the basement.

mattmia2 · 1:12AM

it isn't outdated, they are just putting cheaper systems in most new construction

with hot water if it us cold it is lack of flow, that is either it is air bound somewhere or the other paths are less resistance for the water. or a valve that is closed or came apart internally and closed itself.

EBEBRATT-Ed · 1:50AM

@BruceL

usually one of two things

Air bound or lack of flow.

Questions

Comments

Categories