Basement Radiator doesn't heat

Tharon

I'm hoping someone here can help me. I have a "one pipe" Hot water heating system that feeds old cast iron radiators.
All of the radiators in my house are "above" the main HW line, except for a single radiator in the basement. This radiator only gets about 1/2 as hot as all the rest in the house. It is the second to last in the line, and the radiator after it (which is the last one and "above" the main, has got plenty of heat).

Now, the system was recently drained and fired up for the season. I lowered the temperature of the aquastat to 140-160 and bled all of the radiators. Everything works great EXCEPT for this damn basement radiator. The top of it gets a barely warm, but the bottom is freezing cold. When bled, nothing but water comes out. NO AIR. The valve is on the return side of the radiator and is open.

There are two pipes that feed this radiator from the ceiling, and they come into the radiator at the bottom. One thing that I have noticed is that both pipes in the ceiling that feed this radiator are COLD to the touch, only inches away from where they "T" off from the main. There is a radiator above this one, with lines next to the basement radiator lines, and they are plenty hot to the touch.

I suspect that my basement radiator has a FLOW problem, and that whoever installed it didn't put the monoflo T's in correctly, or maybe didn't put them in at all. By the way, the spacing of the supply and return to this radiator is wider than the radiator width.

If anybody can help, I'd appreciate it. I've called a plumber that specializes in hot water heating and I want to make sure I don't get a dope who doesn't know what he is doing. Thanks for reading.

Unknown

Sounds like the circulator was changed

You'll need to determine the BTUH on that run, the GPH required, and the head loss of the loop, to select the correct circulator from the Mono-flow tee manufacturer's charts.

Noel

Cliff Brady

One pipe gravity

Assuming the one pipe system is the original piping for your house, you still have a "gravity" system. Water circulates around basement in the one pipe from the boiler supply to the boiler return with out being forced through any radiators. Gravity drives the heated water up and the cool water down from the readiators above. In some house the tees to the radiators have diverters to drive the flow to the radiators. Mine does not, they are regular tees. The problem is that the radiator in the basement has no reason for the water to go there because heat wants to rise. If this is all the case, you need a diverter tee or venturi tee to force some flow. A pump and relay could also be an option.

Cliff

Tharon

It definately sounds like a circulation problem. I banged on the cold return pipe comming from the radiator (thats located in the ceiling) and its empty.

Matt Undy

If the pipe is emty you have to convince the air to mov eout of it somewhere. It will block flow. Circulation works by the pressur in water faling down pushing water back up. It is basically a siphon. If you have air in the system that breaks the siphon and stops circulation. Post some pictures so they cna see how the pipes are laid out if it isn't obvious where you can bleed to get that air out. Maybe you need to repair some broken or missing pipe hangers to restore pitch.

Matt

Cliff Brady

Suprised if it is empty

I would be suprised if it is empty unless it is valved off some how. Can you confirm that it is an original single pipe system? If so, you definately need one of the methods I described to get some flow into the radiator. Converted two pipe gravity systems have postive flow going out to all the radiators from the pump. Converted one pipe systems still rely on gravity to get heat up to the radiators from the main. The problem is that the heat doesn't want to go down unless pushed.

Matt Undy

This brings up another question. Did it work before the sytem was drianed and re-filled, has it never worked, or did it stop working at some point in the past?

Matt

Tharon

This radiator was always 1/2 as warm as the others in the house. But now it seems much worse. The system was drained a few months ago to replace the valve on this very radiator, because the wheelhead had broken off and it leaked. The valve is angled. They actually wound up re-packing it and told me to open and close it with vise-grips. Since this radiator is lower than the boiler drain, they told me there was no way to get this valve replaced without having the some contents drain out onto the carpet.

Now I am wondering if this valve is stuck partially closed. The valve has only got about 3/8" - 1/2" of travel before it refuses to budge any further in either direction. I'm afraid I'm going to break it if I force it and have the whole system explode niagra falls in my basement. I wish there was some way to tell if it was indeed fully open. (Its all the way counter-clockwise now).

I have attached a crude drawing of my dilema. Thanks to all for responding.

Mellow_2

nice.......

Love the pics ...... If it was me I would cut the radiator out high enough to put a bucket under the line, when I cut it.( maybe above it) This would catch any water psi.....Than take it out side and replace the valve (this would keep the mess outside) . Reinstall it and make sure you have two monoflow tees.( one tee on supply and return, AND keep the spacing) Rads. below the main need two monoflow tees and need to be spaced. good luck.

P.S. this is on the end of the line and if it never got hot,hot....... it could be it never will with out doing more than this piping.

Matt Undy

I'm thinking that you could crack the union or possibly even tak off the packing nut and stem and put some rags and a pan underneath it, maybe use a shop vac in the pan to suck up the water to get the valve out or at least open it up, clean it out, and replace the gasketing in the valve if not replace the vale entierly. Does the valve travel less than the other valves in the system? Perhaps it is a ball/disc or gate valve and not a globe valve so the stem doesn't travel? If it is bound up it probably is full of some sort of crud. Perhaps the piping or radiator are also blocked by this crud?

Matt

AK

Think I've found the problem!

Well, I did some more investigation and I think I may have uncovered the problem. The SUPPLY line to the basement radiator *DOES NOT* have a MONOFLO TEE, but the RETURN LINE DOES. The supply line is just a regular old "T" junction.
Could this be causing my flow problem?

Mike T., Swampeast MO

Exceptional Drawing!

Really like the way you demonstrated "hot", "warm" and "cool".

My humble guess is that you have two separate problems going on...

First is that you really should have two diverter tees for a downfeed radiator.

Second is that (as with all such arrangements) it can be REALLY difficult to remove the air.

The surest way would be to put in a full-port ball valve after the basement supply connection but before the upstairs supply connection. Put another such valve between the basement and upstairs radiator return connections.

With the circulator running, close both valves. The flow will be first forced through the basement radiatior and then through the upstairs radiator. Vent the basement rad until you get only water for 30 seconds or so, then vent the upstairs radiator. Any remaining air in the basement rad piping will be forced into the upstairs rad where you can easily vent it out. Once you're done venting the air, open both valves fully.

Image shows the flow path with the valves closed. Think like air and water and you'll see that this assures you a very effective way of removing air from that basement rad and it's piping at any time. Don't know how big your mains or nor if you have enough spacing to add the valves. May be a big job--maybe not too bad.

Tharon

Great Idea! I noticed that I had to bleed every rad of quite a bit of a air when I fired the system up - EXCEPT for the basement rad. I couldn't get any air out of it! The main pipe is 3/4" and yes, there is plenty of room to install the valves. However, if I can get circulation IN and OUT of that radiator, the air should rise to the bleeder valve, no?

Mike T., Swampeast MO

With the feed pipes heading down, air can do strange things--it will frequently form a pressurized air pocket in the pipes leading to or from the rad. When that happens, water can't get through--or if it does, only at a trickle.

At the beginning of every heating season there are a number of similar problems posted here about basement rads. My answer is usually to do something, somehow to force the water to flow through the radiator so that it forces the air out with it...

Tharon

Update - I've had a plumber come check out the problem. He thinks I have a trapped air pocket in the return line. I believe he intends to cut into the pipe and install some type of bleeder valve above the rad. He told me that the supply pipe gets plenty hot into the radiator and that it doesn't need a second monoflo. I'll keep you all posted on how we make out.