Old gravity fed boiler

Jsbeckton

I have an old WM 210k P-E-7 boiler that I am assuming was originally gravity fed because the headers are 2.25”. It now has a circ pump on the common return line so the huge pipes seem unnecessary.

My problem is I want to finish the basement but the huge steel pipe hangs well below the joists, presumably to allow more slope back to the boiler when it was gravity fed.

Would it be ok to cut out the steel pipe and instead run copper or fostapex mains higher up between the joists? It would really make the finished basement look a lot better but I am worried that I would be opening up a can of worms because it works fine otherwise.

Thanks!

JUGHNE

Is this a 2 story house?

Paul48

Cast iron radiators?

Jsbeckton

Yes, 2 stories, about 2500sqft

Jamie Hall

That sort of thing has been a number of times -- look around the Wall. The usual difficulty is getting the balance right between radiators/spaces -- but that can be overcome with good piping and possibly some zoning.

JUGHNE

Are the second floor pipes brought down to the basement individually or teed in inside outside walls tied to first floor rads.

If separately you could run individual circuits in PEX to the boiler room and gain zoning control of each rad from manifolds.

Jsbeckton

Yes cast iron rads and every rad is tied in at the basement mains with 1” steel pipe. It’s in a first in last out configuration with the supply/return headers running side by side.

Jsbeckton

I like the idea of zoning control. Would I run 1/2” pex to and from every rad and back to the boiler rather than running 1” headers? Would I then need to group them into zones and then add a circ pump to each zone?

Paul48

Do a home-run system, with supply and return manifolds, and circuit setters on the manifolds.

nicholas bonham-carter

What is the capacity of the boiler in relation to the heatloss of the house? Maybe a buffer tank would help it not short-cycle.—NBC

Jsbeckton

Boiler plate lists the input at 210k BTU and the output at 168k BTU. Does that mean it’s 80% efficient? I was thinking it would have been closer to 50% since it’s so old.

I put my house in HeatCAD a few years back and came up with about 95k BTU heat loss for the 3665 sqft heated area (includes 1034 sqft for basement).

Jsbeckton

Would I need a thermostatic valve on each rad or just zone valves?

Paul48

You could do it either way, but zone valves would probably be the easiest way. You may have height issues with thermostatic valves vs. the old valve, and it's just more invasive. Which is the last thing you want with old piping.

Jsbeckton

Ok, zone valves it is. It’s currently set up with 2 direct return loops running down either side of the house; all on one “zone”. I’d like to split everything into about 3-4 zones to eliminate some cold spots. Is there a distinct advantage of Home-run loops vs direct return loops? There is already a lot of piping, wiring, etc running all over my basement so all the pipes needed for Home run would be adding to the madness so I just want to ensure it’s needed.

Either way I think that i would be using mostly fostapex or similar rather than copper.

Paul48

There's more than one way to "skin a cat". The goal is balanced, proper flow to each radiator. There's no real distinct advantage, one way or the other. Either way is a lot of work, done properly.

Jsbeckton

Thanks. What’s the best was to balance the system? Most of the old rads have what appear to be balancing valves that are accessible but probably haven’t moved for 50 years and don’t want to budge. What are these called? Will try to post a picture.

Jsbeckton

These are the currently installed valves that don’t want to budge

leonz

Jsbeckton said:

I have an old WM 210k P-E-7 boiler that I am assuming was originally gravity fed because the headers are 2.25”. It now has a circ pump on the common return line so the huge pipes seem unnecessary.



My problem is I want to finish the basement but the huge steel pipe hangs well below the joists, presumably to allow more slope back to the boiler when it was gravity fed.



Would it be ok to cut out the steel pipe and instead run copper or fostapex mains higher up between the joists? It would really make the finished basement look a lot better but I am worried that I would be opening up a can of worms because it works fine otherwise.



Thanks!

=====================================================
(1) You will be opening a can of worms.

Is your system set up with an air charge in the radiators to hold some pressure or (2) Is the original open to air expansion tank still in the attic but disconnected??

(3) Do you have anything against a suspended ceiling to hide the piping??

(4) Your going to waste your hard earned money when you do not have to by ripping out the old piping when you can have a suspended ceiling installed to hide the gravity hot water piping.

(5) They obviously installed the circulator due to a previous problem that caused an imbalance in the heating system that was not corrected.

(6) When was the last time the boiler was flushed out to remove any sediment??

(7) when was the boiler and burner system serviced and cleaned last?

(8) You had a well balanced system before and they obviously did not take care of it and as a result the circulator was installed to supposedly correct it.

These systems were designed to operate simply with gravity and very hot water rising in the system.

Start with the boiler first and ask steam heating contractor to come service your boiler as they would be familiar with gravity hot water heating and cool water return piping requiring proper the slope to drain back to the boiler. They will see the problem quickly and fix it.

No sense in wasting money when the system has worked since it was installed except for the installation of a circulator.

Find a good steam contractor from the lists that Dan and Erin have here and go from there.

Jsbeckton

I would be gaining about 100sqft of headspace in 400sqft room vs leaving the overhangs with a drop. I’ll likely spend $5-10k on the basement so the cost of the the fostapex headers adapters etc...would be trivial. It’s more of a question of if this would really be a much bigger job than that. I’m now leaning towards possibly just replacing the boiler next summer anyways.

The last thing I want to do is leave the overhangs now and then end up ripping them out next year anyways.

Jsbeckton

Any thoughts on the balancing valves in the picture? Out of 15 of them only 2 turn anymore.

nicholas bonham-carter

On old valves, the packing nut, just under the handle can be loosened a bit, and that may enable the valve to be closed.
You might want to make some marks, showing the current handle position.—NBC

Jsbeckton

So I’m thinking that I need zone valves, balancing valves and a variable speed circulator that can maintain a constant pressure as zones open/close. Does this sound like a good starting point?

Would this be a good plan whether or not I rip out the oversized steel pipe or just keep it or would that change things?

flat_twin

I got stuck on "it works fine" in the first post. Sounds like you'll be changing a lot of things to make it work fine again. I wouldn't dream of touching our old gravity pipes and radiators. They work fine too. Single zone?

Jsbeckton

By works fine I mean no leaks and the house stays reasonable warm but there are certainly cold spots that I would like to get rid of. Yes, single zone so it’s either all on or all off.

Paul48

Maybe we should back up, and slow down, a bit. You mentioned the chaos of piping and wiring that already exists on the basement ceiling. I have a pretty good idea what you're talking about. I have a 1925 gravity conversion. You can't (shouldn't) sheetrock over that. You can gain head room, but I'd plan on a drop ceiling.

You mentioned cold spots. You need to get a handle on what is happening to cause those. Do you have the results of a room-by-room heat loss? Have you made sure there's enough radiation in those areas? Gravity conversions are notorious for dropping the most restrictive circuits when they are under-pumped. For this heating season, you might want to look at the way the system is pumped. Here is an article that will help determine the circulator that's needed.... https://heatinghelp.com/systems-help-center/sizing-circulators-for-old-gravity-hot-water-heating-systems/

Paul48

Something to consider.....If you can't raise the bridge, lower the water? That opens up the possibility of radiant heat down there.

leonz

Jsbeckton said:

Any thoughts on the balancing valves in the picture? Out of 15 of them only 2 turn anymore.

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Now that we know that;
do you have an Attic??????
Did they rip out the open to air expansion tank out of the attic and replace it with the circulator????????

Is there a bladder expansion tank in the basement?

OR do you know if the heating system had an air charge in each radiator instead a an open to air expansion tank?

They did not take care of the heating system-hence the circulator-which did not exist when that beautiful heating method was installed in your home. It is not needed.

in regard to the radiator valves, If they do not turn they need to be repaired/repacked and or replaced and that is probably why you are having problems with cold spots as the slow even heat is not getting everywhere it needs to go and the cooler water is not returning to the boiler sump and you also may have dirt built up in the old valves as well.

The radiator vents probably do not work either and need to be replaced.

Better to change the valves, replace the vents, flush the radiators and make sure the radiators are set properly to allow gravity flow as you will be making a huge expensive mistake trying to change things as this gravity hot water heating system was not taken care of by the previous owner.

Paul48

@leonz

How would you propose he run a gravity system with an oil or gas-fired boiler, as opposed to a coal boiler?

JUGHNE

leonz, can you show us a modern residential sized boiler that has two 2" inlets in the bottom and two 3-4" outlets in the top?.
That perhaps would have been the original taps.

From the gravity systems I have seen there was no boiler connection smaller than 2" in the smallest house.

leonz

It is entirely possible to adapt a bell fitting or fittings to the pipe riser(s) size from the steam chest tapping(s) and the same return pipe and reducing bell to the return tapping in the boiler sump.

The hot boiling water in a two+ inch tapping is going to rise from the steam chest to its tallest point and migrate to the radiation and then the cooler water will fall to the boiler sump to be reheated.

Why screw it up and make massive changes to a heating system that just needs some TLC?

It would not take much to request a change order for the custom construction for larger tapping's in a new boiler. If they will not do it find another boiler builder. The new boiler would have to pass whatever testing ASME, H stamp and CSL testing is needed before it leaves the boiler builder anyway.

Jsbeckton

@Paul48

Yes, plan drop ceilings so I still have access, just want those drops 7’ off the ground rather than 5-6’ with the pipes as low as they are now.

No expansion tank in attic, it’s down by the boiler.

Cold spots are likely the result of changes over the years by many owners. For example there is an addition over the garage that was “tacked on” heating wise as far as I can tell.

Also a sliding glass door was added to the kitchen which required removing the radiator. It was replaced with 2 under cabinet hot water blowers and radiant heat under the floor. However, the radiant floor and blowers are likely designed to run much more frequently than the cast iron rads so the kitchen quickly cools while other rooms stay warm.

Jsbeckton

@leonz

As noted above, there were many more changes over the years so it’s not like the original design is intact and they just added a circulator.

Given the mix of heating elements I think that I need to split this up into zones because there is no where to put a radiator in the kitchen anymore because all of the wall space is now gone.

KasiP

Gravity
TOO much circulator!! It is a gravity system so it has hardly any head. It should be piped a P/S. This will reduce the velocity in the gravity system while not cooling down the pre heated water going through the boiler when not running.

Do it once / Do it right! Call a pro!

leonz

You can always rehang the steel pipe higher in the ceiling joists after draining the boiler and piping and make new connections.

Think of a water tower fed municipal water system which creates head pressure to feed potable water they have lots fo head pressure from the water in the water tower.

We have many water towers in my immediate area in and around Ithaca, NY that do this job very well and many ground placed water tanks at higher elevations to provide adequate flow rates for fire hydrant flow rates and potable water in many municipalities.

If it were me I would call in a B+G rep and pay for his lunch and ask what you need to do to return it to a gravity system like it was as All you may need is a larger open to air steel expansion tank in the attic to handle all the heating needs to eliminate both the circulator and the cold spots caused by the remodeling and radiant floor and still be able to heat the basement.

If you have enough water in the attic it will provide enough head to push the hot water through the system and back to the boiler with smaller piping, it is no different than a water tower or a gravity fed municipal water system providing potable water.

Using Dan's example of how an open to air steel expansion tank in the attic can be plumbed in an attic to allow the warm water to migrate faster in the heating loop by installing a Tee in the base of the tank to connect a riser pipe and a return pipe to the boiler lets the hot water move faster through the system and also return warmer water to the boiler sump to be reheated.

Flushing out the old radiators, repairing or replacing the old radiator valves that do not work, adding TRV's if possible, and a large enough storage tank in the attic to provide adequate head pressure, raising the piping in the ceiling joists by cutting the pipes and reconnecting them higher in the ceiling joists would allow a drop ceiling and perhaps panel radiators in the basement would be worth examining more intently as there is a problem with delivering heat to the home.

Gravity hot water heat is a slow even heat through an entire home or building height (of three stories) and has always worked courtesy of the dead men and could be improved by using TRVs if possible.

Harvey Ramer

> @Jsbeckton said:
> I have an old WM 210k P-E-7 boiler that I am assuming was originally gravity fed because the headers are 2.25”. It now has a circ pump on the common return line so the huge pipes seem unnecessary.
>
> My problem is I want to finish the basement but the huge steel pipe hangs well below the joists, presumably to allow more slope back to the boiler when it was gravity fed.
>
> Would it be ok to cut out the steel pipe and instead run copper or fostapex mains higher up between the joists? It would really make the finished basement look a lot better but I am worried that I would be opening up a can of worms because it works fine otherwise.
>
> Thanks!

You certainly can! There is no issue with that at all. One of the better ways is to connect fostapex to each rad riser and bring it back to a manifold. That make flow balancing and zoning quite easy.

Jsbeckton

I scheduled a reputable local company to inspect my boiler on Friday and while he is there I am going to ask him what he thinks. Hoping I get an old guy that’s been around the block rather than a kid with a manual

JUGHNE

Do you have 15 sets of pipe (30 pipes total) poking down into the basement?
One issue I could imagine is if some risers for the 2nd floor hung below the floor joists and end up being in a location that cutting and threading a new end in order to get the PEX connection up between the floor joists is nearly impossible.

Jsbeckton

I have 4 pipes, 2 supply/return headers running down both sides of the basement. Fortunately all risers are just 1” steel and have elbows and/or unions going to the exterior walls well above the bottom of the joists so I should be able to maintain the threaded ends to adapt to the fostapex.

JUGHNE

You are in luck!

unclejohn

Before you run out and get a lot of zone valves remember you have to install tstats and run wire to them. I think your over worrying about balancing. If you want to replace big pipe with small pipe go ahead it will work as well as before. Your gonna need at least 1 1/4" with that BTU.

Jsbeckton

I’m thinking just 2, possibly 3 zones. Understood that I need a tstat for each.