Radiator stone cold

[sophiecentaur]

I think it was considered the best possible system for decades in some areas (cost and efficiency). Yes, it has problems.

A couple of times I had to have the service people come out and shim up a radiator to eliminate excess banging. On rare occasions, the banging is AWFUL; usually it's minor.

Heating bills are high but not what they would be if my house had electric heat.

And haven't they heard about water circulation systems? They are excellent and last for years with very little maintenance (or banging).
I remain gobsmacked by what I have learned on the thread!

 

[JBA]

Back to assuming this is really a water circulation system (and such systems are common for floor heating systems). It would be assumed that the discharge pressure of the pump (I am assuming the pump is a centrifugal and is in the basement) would be greater than the head required to lift water to this highest point in your system even if the discharge pipe started full of air and therefore not acting as siphon to balance the elevation pressure differential created.

At the same time, maybe as suggested earlier, the flow through the lower system is preventing this required level of pump discharge pressure required to overcome the elevation head to be attained.

Based upon this, and that your problem radiator has a manual valve, which suggests that all of the radiators would also be so equipped, I would suggest that you systematically try reducing the flow through some (but not all, for safety) of the lower radiators by successively closing the inlet valves on those units and checking after each closing to see what effect this might have in restoring flow to the problem bathroom radiator.

 

[phinds]

And haven't they heard about water circulation systems?

There ARE hot water radiators, I understand, but I've never experienced them. Greg is sure that's what his is although I'm perplexed as to how he can have the situation he has if it is a closed loop system with a feed and a return all the way around the house.

I think perhaps hot water just doesn't cut it in really cold climates. Live steam provides a lot of heat and some of the old houses are large.

 

[phinds]

Back to assuming this is really a water circulation system (and such systems are common for floor heating ...

But he's not talking about floor heating he's talking about radiators.

 

[JBA]

The basic heating principle is the same and just as a note, in industrial installations closed cycle thermal transfer fluid heating systems are common. We used that process in the original design of the heating system for the entire Alyeska terminal facility in Valdez Alaska some 45 years ago.

To this point the target of this thread has become an "it is vs it isn't this kind of system" debate which is no help in assisting to try and address the original problem as posted.

To the best of my knowledge, the radiators for all steam systems have air vent valves that are temperature operated, so if he has one of these on his radiator I would suspect he would know that. If it does not have one then I doubt it is a steam system.

At the same time, I am not contesting the fact that due to the heat carrying capability of steam that those systems are more efficient; but, that doesn't mean that is the only type of liquid heating system ever installed in a residence.

 

[CWatters]

This is a water system. It must cycle.

The vast majority of houses in the UK are water system, either open vented or pressurised so we are very familiar with them over here.

Most of ours have the radiators connected in parallel not in series so if one is blocked that doesn't stop the flow to the others.

It's very common for corrosion products to create gas (which tends to stop rads near the top of the house/system getting hot) and/or sludge (which tends to stop lower rads getting hot or blocks the whole system).

It's very common for these systems to have problems if they are off over the summer. The gas tends to build up and the sludge settles out. Some systems run the circulating pump at regular intervals even when the heating is off to prevent the sludge settling out and to circulate gas past the auto bleed if fitted.

See also my earlier post about corrosion inhibitor. Saves a lot of trouble.

 

[DaveC426913]

Well, Canadians have not discovered steam yet. Give it time. After all, you guys just got fire a few years ago

Aw man, fire was a b*tch! We couldn't pick it up from lightning, our lightning freezes before it hits the ground.


Then again, we invented flash freezing before we invented the wheel!

 

[Averagesupernova]

To this point the target of this thread has become an "it is vs it isn't this kind of system" debate which is no help in assisting to try and address the original problem as posted.

I would think that is the first thing that needs to be established.

 

[sophiecentaur]

This has happened before. The OP has gone and scarpered when we all want to get this thing working for him. Greg, of all people. (Do you think this could be a test, guys?)

 

[Greg Bernhardt]

This has happened before. The OP has gone and scarpered when we all want to get this thing working for him. Greg, of all people. (Do you think this could be a test, guys?)

Still here, got busy and a little lost with some of the tangent discussion. My system is water. Bought a key to bleed the Rads tomorrow. A new dev though. I turned the heat up 10 degrees and the rad did heat up then, but if I raise by 2-3 degrees it will stay stone cold. Just strange that every other rad heats up nice.

 

[Averagesupernova]

My guess is that raising the heat by 2 to 3 degrees causes a short run time. The room which the thermostat is in warms up quickly. When you bump it by 10 degrees the boiler runs longer and is long enough to get hot water to the troubled radiator. The cause? Probably something nearly blocked off.

 

[sophiecentaur]

Cold top = air
Cold bottom= sludge
Slow / never heating= could be both.

 

[DaveC426913]

Cold top = air
Cold bottom= sludge
Slow / never heating= could be both.

What is strange is that even the pipe from the floor leading to the valve is cold.

Gotta be d] other.

 

[Greg Bernhardt]

Cold top = air
Cold bottom= sludge
Slow / never heating= could be both.

What about one side not heating. I have a few where a few back vertical coils don't heat up. fyi, I believe several of my rads are original and nearly 100 years old.

 

[DaveC426913]

What about one side not heating. I have a few where a few back vertical coils don't heat up. fyi, I believe several of my rads are original and nearly 100 years old.

I think we can pretty safely conclude that there's some blockage, though that might not be the gamut of the problem.

 

[Bystander]

How "hard" is your water in Wisconsin?

 

[sophiecentaur]

We have Flushing and Magnatek gizmos to catch iron powder in UK.
100 yr old rads can develop leaks if you flush them out. Just sayin'.

 

[Bystander]

... plus, gypsum solubility decreases with increasing temperature ... "Mr. Coffee" and related "knock-offs" got clinkered shut in a year or less in SW Kansas by stuff dropping out of solution.

 

[sophiecentaur]

What about one side not heating.

The flow is usually (not always, when the piping doesn't support it) in at the top, one end and out at the bottom, the other. If the upstream half is cold, the bottom is probably clogged near the input. If the downstream half is cold then the (large) bubble at the top is probably being pushed towards that end and the water never gets to the top of those tubes. When the rad water level is nearly down to the tops of the tubes, it ends up as a series of weirs with the water level getting lower and eventually stopping water getting over the tops of some downstream tubes.
Are the rads cast iron or pressed steel construction? Replacing cast rads could cost a fair bit and you have to ask yourself where a leak could exist.