Uneven Radiator Heating

[Pavel314]

I have a big, old farm house with an oil-fired furnance and old fashioned hot water radiators. A couple of weeks ago, the radiators went cold although the furnace would still fire. The furnace repairman came out and said that the circulator pump was fine but that the check valve had stuck. He opened it manually, closed it, and watched the furnace go through a heating cycle.

A few days later, the heat stopped circulating again. I opened the check valve and closed it, as the man had shown me how to do, but that didn't help. I called the oil company for repairs but they said that I had to get a plumber for the check valve problem.

The plumber came out and after checking the situation, said that the best thing to do was to just leave the check valve open manually all the time, that the check valve wasn't that important since I had a hydronic system, with one pipe in a closed loop. So I left it open.

The problem now is that the radiators on the north side of the house don't heat well while those on the south side do. All have been checked for air lock and they're fine.

From the furnace, the hot water passes through the check valve and into a T that sends the water north or south. I'm going to try adjusting the valves on the north and south feed lines to try to even out the water flow. Any other ideas or comments?

Paul

[ransley]

I guess the check valve is there because of uneven heating or to shut off an area, but does it close down the overheated side, if so try closing it. Or are there 2 valves, one pump, 2 stats to balance it. Pumps do wear internaly, is water comming out the radiators when boiler is cool but pump is on. Im no pro just guessing.

[Pavel314]

Here's the layout, as best I can describe with ASCII characters:

------- Valve ----->

North Side Radiators | 4 Upstairs, 4 Downstairs | FURNACE --- Hot Water Pump --->Check Valve-->--- (T-Joint) | | -------------------->

South Side Radiators 1 Upstairs, 2 Downstairs

I had hoped to find a valve on the main line to the south side but there is none. What isn't clear is why the situation changed. The check valve only prevents water from coming backwards from the T-joint into the furnace so whether it's open manually or automatically should be irrelevant. Unless the larger number of north side radiators causes inertia with the check valve open and diverts the water flow into the south side.

Paul

[Pavel314]

=A0 =A0 =A0 =A0 =A0 =A0------- Valve ----->

=A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A04

=A0 =A0 =A0 =A0 =A0 =A0|

=A0 =A0 =A0 =A0 =A0 =A0|

=A0 =A0 =A0 =A0 =A0 =A0|

=A0 =A0 =A0 =A0 =A0 =A0-------------------->

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A01

Sorry, my drawing didn't come across as I intended; to the right of the valve on the upper arm it should say North Side Radiators, 4 upstairs, 4 downstairs. After the bottom arm, it should say South Side Radiators, 1 upstairs, 2 downstairs.

Paul

[Eric in North TX]

Here is a radical thought, how about just replacing the known defective part?

[Evan]

So Paul, just so we are clear here you are wondering why in a Hydronic heating system using only one circulating pump,

*NO* zone balancing valves and zones with vastly different run lengths and uneven heating loads doesn't heat evenly ???

Wow... It is a miracle it worked to begin with... That magic check valve that somehow made things work...

Please at least tell us that the piping for the longer run is using larger diameter piping than the shorter run, say 3/4" pipes as opposed to the typical 1/2" piping...

Usually in hydronic systems there are zone balancing valves located near the boiler just off of the manifold pipe so that shorter zones can have their flow rate restricted so that the longer run gets a chance to heat...

It sounds like your ONE circulating pump is wearing out and while it is still pumping some water, it is NOT pumping enough volume to adequately supply the flow rate required in a horrendously lopsided system with no capacity to have the flow rate on the shorter run restricted...

You could simply replace the check valve like another poster here has suggested but its failure has uncovered some important oversights that were made in the initial design of your system...

If it were my house, I would find a plumber who has extensive hydronic heating system experience to upgrade your poorly designed system so that each zone has its own circulating pump and zone balancing valve...

Get someone out who actually knows what they are doing with hydronic heating systems to evaluate what you have and recommend the best remediation which will solve your problem, not a "pipe mechanic" plumber who seemingly only knows how to solder pipes together and fix broken faucets whose only ill-advised recommendation was to keep a faulty check valve manually opened rather than repair or replace it...

~~ Evan

[ransley]

I will guess the check valve kept the hot area from overheating, not what you think controling the colder area, so close it, is the thermostat in the in the cold area.

[Pavel314]

I agree, I think I need an expert opinion. The heating system was in the house when my wife moved here 30 years ago, God only knows how old it was at that time. The south wing of the house is the original house, from the 1930's. When they put the new, larger wing on the house, in the 1950's I would guess, they probably just added a T to the line and tapped off from that for the north side radiators.

We replaced the original furnace ten years ago but the piping and all remained as it was and there was never any problem until the recent check-valve problem. The check valve, I believe, was from the original system.

The system at least needs to have a new check valve and a control valve on the south line to balance things out if needs be. I guess I could get away with just turning down the valves at each of the three radiators on the south side but a main line valve would be better.

Paul

[Pavel314]

That makes sense. The check valve would hold back the water until the pump started. Now, as the water heats, it rises into the path of least back-pressure and starts a thermal flow before the pump kicks in. Yes, the thermostat is in the cold area. I never thought of that before, but that compounds the problem, keeping the furnace running longer and pumping more heat into the already hot side.

Paul

[ransley]

Can a balance valve be manualy cutback in the meantime

[Tony]

Looks like you should make it 2 zone heating. Parallel systems aren't easy to control.

[Ed Pawlowski]

Let me start with the basics. You don't have a furnace. You have a boiler. Furnaces heat air, boilers heat water.

If the check valve is know to be bad, it should be replaced.

Before you do that though, how old is the boiler? If it is very old, you can get a new one for free. Yes, free. Here is how I did it.

I replaced my 30 year old boiler with a System 2000 by

The state of CT will finance upgrades like that at

0% for 10 years. Payment is less than $70. The state also gave me a $500 rebate. My oil use dropped by 38% in the 15 months I've had it. The oil saving alone is enough to pay for the boiler, but on top of that, I got a $1500 tax credit.

Do yourself a favor and look into new equipment. IMO, the System 2000 is the most efficient out there.

[Evan]

com=A0The state of CT will finance upgrades like that at

How does getting financed at 0% for 10 years qualify as FREE ??? Definitely not paying into some huge corporations profit margins, but you still have to repay what you borrowed... It sounds like you had to front quite a bit of money to actually have the work done and only received approval for the program later based on an inspection of the completed installation...

It is good that your decrease in oil use will offset your boiler upgrade costs, but it sounds like your situation was possible because of that program offered by the State of Connecticut and your quick action to apply for a spot in it... Energy savings aside, why on earth would you ever front thousands of dollars to receive a $1,500 tax credit ??? You still had to spend thousands of dollars of your own cash, or in your specific case state money that has been loaned to you, in order to get that tax credit... That sounds a lot to me like a lottery psych-out, get you seeing the tax credit dollar signs to distract you from the fact you had to spend quite a bit of money to receive it...

Do you have any numbers on how much funding Connecticut put into that program ???

~~ Evan

[Ed Pawlowski]

"Evan" wrote

Actually, you are wrong. You can apply for the loan before the system is installed. Payment terms varies by dealer, of course, but you may not need any upfront money. I've not had to put out any cash from my pocket and the savings in oil has not increased my monthly payments for heat/utilities/loan combined. Even with a consumer loan it is possible to save enough to make the payments. Savings varies with each house so you savings may be greater or less.

Right now the new boiler is costing me nothing at all. Once the loan is paid, money will continue to go into may pocket and I'll be way ahead.

The saving is aside from the tax credit. That is just a bonus on top of the already big savings. My initial decision was based on oil savings only. I did not know about the rebate until after the job was done. The rebate was equal to 7 loan payments.

As I stated, the tax credit is a bonus. I recommended the OP review what he has and consider potential savings. The house is old and perhaps the boiler is old too. If that is the case, why keep paying for oil when you can pay the same money today and have a new boiler, better hot water heating, increased comfort and potential savings in repair costs for the old heater. Once paid for, the savings go right into your pocket.

One caveat though. If oil goes back to 85¢ a gallon again you won't save any money. At $3 though, I'll have even faster payback. What do you think the price of oil will be in the next few years?

No idea at all, but in the millions.