Basement radiator heating mystery

samster101

We just moved into a house with hot water radiators and it's been quite the journey! We've replaced many parts in the boiler system already (also in the basement) and we're down to the basement radiator.

The basement radiator was the only rad that was heating up before we replaced the pressure relieving valve (PRV). Once we replaced the PRV, the pressure rose from 10psi to 20psi and all the rads on the main floor (4 rads) and 2nd floor (4 rads) are heating up fine. However, the basement rad has now stopped heating up and the inflow and outflow pipes are cold.

I tried bleeding the basement radiator - this causes the inflow pipe to get hot and heats up the entire rad. I noticed the pressure through the bleeder reduces after bleeding it for a few minutes, but since the rad and the in/out pipes are hot, I recap the bleeder screw.

After 15 minutes, I go back and notice the inflow pipe is cold again, the outflow pipe and rad are warm (not hot), then the entire thing cools down again. I tried rebleeding and repeating the process and the same thing happens each time.

What I'm trying to figure out is:

-Is it an inflow issue since the pressure is diverting all the hot water upstairs after the PVR is replaced?
-Or, is it an outflow issue where there's a block in the outflow pipes, causing the hot water not being able to flow the rad when the bleeder is closed?

JStar

Do you have a picture of the radiator and where it attaches to the system?

samster101

Here's the basement rad and a photo of the boiler.

Abracadabra

I'm not a hot water heating guy, but wouldn't that radiator work better if the in and out were on opposite sides? Is there an expansion tank on the system? You said that pressure thru the bleeder drops after you bleed the system for a while. How low does pressure drop on the gauge?

samster101

All of our rads have in's/out's on the same side and it's fine so far...

There is an expansion tank.

I meant the pressure of the water squirting out of the rad goes from flying all over the place to a thin stream of water coming out. The PSI from the gauge on the boiler drops from 22 to 20.

nicholas bonham-carter

There should be a constant pressure on the escaping water, as you finish bleeding the rads. What about checking the expansion tank for being waterlogged, and allowing the pressure to shoot up?--NBC

samster101

If there's an issue with the expansion tank, would it only affect the basement rad?

Techman

Does air come out when the bleed port is opened or just water? Are both in/out valves open? Do both in/out pipes(2-3') before/after the rad get hot after bleeding?

icesailor

I just confused your issue with someone else's.

Here:

Some of your problems may have more to do with that ancient Watts 1156F Pressure reducing Valve being cast iron and connected to a brass 9D Back Flow Preventer. There is a tag on PRV that gives the model # and also the date of manufacturing. It is probably around the same date as the boiler installation.

You need to post photos of the offending radiator and the piping where it connects to the main. Down-fed radiators can be difficult to make work when connected to zone piping that feeds overhead radiators and also, the down fed one. Once bled of air, there should never be any air in a down fed radiator. Air rises.

Fixed it.

samster101

Hi Icesailor & Techman,

Thanks for the advice!

We just replaced the Watts 1156F PRV and back flow preventer this week, it's the same models but new. The pipes are inside the drywall and I prefer not to open it up if I didn't have to.

When bleeding, there's never air - just water coming out.

Both in/out pipes and the rad gets hot after bleeding it for a while but once we close the bleeder it turns cold.

I actually think there could be something stuck in the outflow end instead of the inflow side.

Suggestions?

icesailor

Nothing is "stuck" inside. There is a problem where it is piped in to the main. That getting water, finally hot, is a classic sign of either the flow valve on the radiator not working and closed, or being piped improperly. Especially of connected into a Monoflow main circuit with radiators above it.

If possible, can you show piping at the main? The problem isn't in the wall. Post a picture of the radiator too.

gcp13

The (prv) pressure reducing valve maintains pressure just enough to get to the top of the highest radiator no more is needed. 20 PSI will get you 46 feet high
Probably more than you need
And 1156 PRV is 25 max range usually only set for 15 pounds
I would shut one valve at the radiator and bleed until you get water and then open it then shut the 2nd one and bleed it the see if you get circulation
If not check valves at the boiler that go to that radiator and make sure they are open.
If that's ok you can shut off the valves going up to the rest of the house and see if it starts to circulate the basement

samster101

Sorry, it's our first home and the first time working with rads so please excuse me if I'm asking newbie questions.

Is there a way to reduce the PSI? We tried draining some water from the boiler and it still goes back up to 22.

How do you shut off a valve on a radiator?

Paul48

http://media.wattswater.com/1910265.pdf Here is the instructions for the PRV(adjusting pressure). To close one of the valves at the radiator, turn the handle clock-wise. Counter clock-wise to open.

Zman

The first question is "What changed?" The lower level worked, then it didn't. If you didn't open or close valves, it sure sounds like air. I know you have tried bleeding, it is not always that easy.
Is this a monoflow? If you post pictures of the tees off the main or a drawing of the piping layout it would help.
Carl

Paul48

You may have to do whatever is necessary to gain access to the point at which the supply and return for that radiator join the mains. If someone sheetrocked over it, the next lesson will be sheetrock repair.

SWEI

gcp13 said:

The (prv) pressure reducing valve maintains pressure just enough to get to the top of the highest radiator no more is needed. 20 PSI will get you 46 feet high

Probably more than you need

It's best to leave at least a few PSI at the top of the system, especially when the high limit (or the top of the ODR curve) is 180˚F or higher. 20 PSI in a 35 foot system will leave 5 PSI at the high point.

icesailor

Which is why the higher pressure is often a good idea. Water at 12# PSI pressure boils at 244 degrees. At atmospheric pressure, 212 degrees. At the top of a heating system, you never know what the actual pressure is. Especially when air is involved.

If the radiators on the first (and second) floor are working, the radiator in the cellar should be working because there is enough pressure. You just bought the house. As I understand, you don't really know if the radiator worked or not when everything else is working. If the radiator in the cellar is fed on one ebd, like the supply and return are on the same end, they will often not heat the whole radiator. Just the end section. If there is no air in the affected radiator, and the ones above it are working, there's something wrong.

Post photos of the radiator and the piping connections to the main.

gcp13

Sounds good. I thought I would let the him know how the PRV works and that the pressure is not the problem for the basement. Depending on how High the building is and the safety rating you never want the pressure to be too close to that safety. Most residential boilers are 30 psi max.

gcp13

Old gravity systems never had pressure at the top floor. As long as the overflow tank in the attic was full they would have
Circulation with 7 degree diff. In temp.

SWEI

Open systems are different (and becoming quite rare these days.)

samster101

I checked up on the basement and also contacted the old owner - apparently the rad was working and was the hottest one when she was living in the house.

After moving in, we moved a rad from vertical to horizatonal (same spot) and changed up some parts in the boiler room (PRV, backflow preventer, shutoff valve) to get the rads on the second floor working. Now, the basement rad isn't working.

I've attached photos. I noticed today that there's a small leak from the side of the rad. Could this be the culprit?

samster101

The tiny hole turned into a huge crack so we decided to remove it all together and switch it to an electric baseboard heater. Would removing a rad affect the pressure in the rad/boiler system?

icesailor

I don't know where this has gone to. I never saw the old radiator photos from before. And then the ones recently. Its one of THOSE radiators. Do the two pipes that go into the radiator get hot?

Something was changed. Someone that knows what they are looking at needs to look at it.

I've never dealt with a dual feed at one end radiator. They either need a very low flow or a very high flow to work. Or else that won't work.

samster101

The pipes only get hot when we're bleeding it. When that happens, they are both hot (the red one is hotter than the green)

gcp13

Leak on radiator isn't good but will not prevent it from heating up.
You will have to replace that radiator and it would be better to pipe feed and return from different sides.
You have to follow the pipes from the radiator to the boiler and make sure all valves are open. If any of the handles rotate and do not stop the gate could be broken on the valve
Do you have a photo from where the pipes for the basement radiator branch off from the boiler?
Some piping arrangements had balancing valves that you could throttle certain sections down to slow it down so it would circulate in other areas

unclejohn

The air is not in the rad it's in the pipe going to the rad. You need to bleed the return and supply in the ceiling, or at the high point.

Zman

I still think air is the most likely culprit.
Have you operated those gate valves? Some of them will break in the closed position and it is very hard to tell.
When the radiator was removed, what happened to the pipes? Is it possible it was piped in series? The old timers would not have done it that way, the radiator in you picture looks like it is piped in copper and not original to the home.

Carl

icesailor

If it worked once, and doesn't work now, something changed.

The poster said that all the other radiators in the house were the same, with both pipes on one end. As those radiators were designed to be connected. They are hot water radiators. If they were originally designed to be on gravity, that would be slow flow. If someone put a placer mining pump on the system and it is now grossly over pumped, the water in the above main might be just be zipping bye with nary a thought of stepping down.

Who knows what some unknowing boiler replacer did, not understanding what they were doing. We ALL (should) know that down fed radiators on the same loop or main as radiators above the main are difficult animals to make work. If it is a cellar radiator, it needs to be on its own zone with its own circulator. Unless it is part of a parallel reverse return.

Absolute #1 task of oddball troubleshooting: "If it worked once, and it doesn't work now, what changed?" Find that out and you solve the problem.

And if the above radiators had the dual-one side inlets, having air in the radiators shouldn't effect the flow. Just the amount of heated surface area. Either those valves are broken and one is closed, or something changed in the boiler change.

You have to think like water. Water doesn't care where it goes. Sometimes, it just doesn't like the path you provide for it. Its like trying to get a difficult child to eat his peas. If the dog is around, he will feed the dog, but still not eat his peas.

Lance

This is one case air blockage or a bad valve is the cause. The change was air got introduced when a new part was added.

icesailor

With the radiator fed on the bottom, and the air bled out (even if it was only partially bled out), and the main feeding the upstairs radiator, filled, and the radiators are hot, there can't be any air in the mains or the upstairs radiators wouldn't be hot. There may be a high point off the main and leading to down pipes to the basement radiator, but that is a partial cause. If someone put up a ceiling and covered an access, it needs to be opened for access.

If you can get hot water at both supplies at the bottom of the radiator, when you bleed, then at least one side hasn't an air blockage. The other side can be blocked, or one of those valves is broken. It worked splendidly before the boiler change. Now it doesn't work. What changed? Crank the pressure to 26# overnight and see if it starts to circulate. Let the pressure absorb the air.

You need a graduate of The Institute of Low Technology to look at it. Don't over think it. It would be nice to see some pictures though.

ronewold

Holy Cow! Did I hear correctly that, without trying any serious troubleshooting, you have decided to put in an electric baseboard heater? This is an incredibly thoughtless solution to the problem. This is how systems end up all confuzzled like this one was when you found it. If you are lucky, the original problem won't come back, but since you don't know what the problem was, there is no way to know if you won't be back here with no working radiators next week. Or worse, some years down the road some heating contractor is going to be scratching his head in your basement wondering where those two mystery pipes going into the wall are supposed to go... and he should be charging you by the hour to figure it out.
If you are patient, the right person who has seen it all twice will show up here and tell you what is happening without having to see the system. However, there are lots of people here now who can help you if you are willing to actually show us what you are dealing with. It sounds like you are quite willing to poke away at your heating system with very little information, but you are unwilling to breach drywall for any reason. Think about it.

gcp13

Ditto

gcp13

Think about the cost of electricity vs an hour with a qualified heating contractor to fix or at least give you better options.
You already have a heating system why
Mess things up.
Keep in mind not to many systems that old originally had basement radiators.
That was probably added later.

Furnacelady

Rule No. 1 - Always do the easy stuff first.
- There just was an article on PRV's and who leaves them open and who leaves them closed. Response was about 50-50. So that's not it.
- Why do electric when you could have bought an 8 foot HW baseboard, some copper valves and dielectric fittings. But that's not the problem either.
- Hint - what happens to many electric motors when they start to fail. They work ok when cold and fail when hot.
- Change the pump and flanges.

Furnacelady

Forgot to mention, put your boiler temp around 140 degrees. Oxidation problem is worse to figure out and if it is up past 170 degrees that could be adding to the problem.

Furnacelady

If you have air in the system most often you can hear it as it goes through the pump. Also now would be a great time to put in a simplem low water cut-off for safety reasons, it might save you from having to replace your boiler some day. Cheap insurance.