Hot water heating system - one baseboard stays cold

gjer

I have hot water heating in the house -- baseboards on the first floor, and hot water radiators on the second. Only 1 thermostat. The second floor everything works too well and gets too hot in every room. The first floor is open space, with 4 baseboard heaters. 3 work well, but the last one stays cold.

I have bled it for a while until hot water comes out. It still stays cold. I don't know how the pipes are connected or how this is connected to the other 3 on the floor because it is pretty far from the other 3. I can't see the pipes as they are under the flooring. I have pictures below that may help.

retiredguy

A lot more information is needed such as how the radiation is connected, and etc. One thing I will ask, is that piece of baseboard that you show in the picture the one that is not heating. If so, does the piping to and from that finned tube get as hot as the rest of the baseboard units? If it does, the problem may be that the element is mounted too close to the floor and that the fins should be rotated 90 degrees so the air can enter the finned tube area and flow upward. Also the element is in poor condition and very dirty and the cover must be in place to provide proper heating.

gjer

@retiredguy Thank you for your response. So there is a cover, I took it off for the pic. You are right, it is in poor condition. We recently bought the house and it was this beat up.

The water flow goes from left to right. It is cold on both sides. When I bleed it, that side starts getting warm and hot, but the heat does not move down the pipe. The other side still stays cold. If I stop bleeding it, even the hot side cools off and it stays cold. So I can get hot water out of it if I bleed it long enough, but it doesn't solve the problem.

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hot_rod

You might try bumping the boiler pressure to 12-15 psi. Turn the slotted screw on top of the Caleffi valve a small amount
Additional pressure sometimes helps get an air lock moving

It looks like a couple balance valved where the piping splits, have those been turned 

leonz

Is this heating system a converted gravity hot water system??

Are those valves in the larger pipes half closed??

Is the relief valve for the boiler next to the wall???

You do not appear to have a low water cut off switch, air scoop, expansion tank or
a compression tank with an airtrol valve to maintain the point of pressure change.

The wiring is not up to code either.

gjer

@hot_rod they look like half closed, but I haven't touched them.

@leonz the relief valve looks next to the wall in the pic, but it's actually about 3 feet away. Judging from all the things you pointed out missing, and the wiring, it sounds like this whole thing needs to be redone. What kind of cost should I expect to get it up to code and add the missing parts?

leonz

gjer said:

@hot_rod they look like half closed, but I haven't touched them.

@leonz the relief valve looks next to the wall in the pic, but it's actually about 3 feet away. Judging from all the things you pointed out missing, and the wiring, it sounds like this whole thing needs to be redone. What kind of cost should I expect to get it up to code and add the missing parts?

================================================================

UMMM, ouch!!!!!!!!!!!!!!!!!!

If it were me being a fussy homeowner that likes to sleep nights-
I think your heating system was a gravity hot water system that had an open to air expansion tank either in the attic or the highest point in the living space.

The boiler should be moved away from the existing wall and placed on concrete blocks to get it off the floor.

I would replace all the near boiler copper with black iron pipe as I have had propress fittings blow apart and the resulting flood made a mess in my laundry room that also has the coal stoker in it. Copper scrap is still valuable at a scrap yard.

The circulator cannot be segregated to be changed as it has no isolation valves and the water in the system could come back through the boiler and flood on the boiler.

The boiler should be piped pumping away like mine is to help remove air bubbles quickly.
With as large a system as you apparently have in water volume I would use a steel compression tank due to its simplicity and the fact that you never have to bleed baseboard which saves on the knees AND you never ever have to deal with automatic air valves that will leak as there are none.

I have a 15 gallon steel compression tank with an end sight glass gauge and it saves me a great deal of work and worry about how my heating system is working as the circulator is always flooded with water and the ATF-12 airtrol valve in the base of the tank allows the air bubbles if any to rise into the tank and enter the water and be absorbed in the air blanket above the water line of the steel compression tank.
The steel compression tank is elevated above the boiler and normally held in place with pipe strapping but can be secured with lumber by making a shelf hung from the ceiling strong enough to support it.
A steel compression tank that employs an ATF-12 airtrol valve uses a ratio of 1/3 air to 2/3's water to maintain the point of no pressure change to allow a circulator to work with no difficulty.

You could also use a bladder expansion tank but I would be worried about the price of the bladder expansion tank as you may need a very large one that would sit on the floor. You would also need
an air scoop and with tappings large enough to equal the largest tapping on the top of the boiler if the boiler has a baffle plate as part of the casting to divert the air bubbles upward to be taken out of the water flow.

The other thing is your going to need a bunch of automatic air eliminators or one big one to get rid of all that trapped air.

You could use an air scoop to feed the air bubbles into the ATF-12 Airtrol valve and avoid having an expansion tank.

I am going to suggest to you that you invest in three of Mr. Holohans books on hot water heating so you understand what you are looking at and do not get taken advantage of:

The first one is CLASSIC HYDRONICS which is a wire bound heavy paperback that will let you fold the pages over and set the book down while you are looking at things. The second one is PUMPING AWAY. The third one is HOW COME?

I have all three of these fine well written books that help me design my coal stoker boilers hot water heating systems new plumbing layout using a pump module explained in great detail in the book pumping away and using the pump module layout to connect my internal air separator(IAS), steel compression tank with its sight glass gauge and the ATF-12 AIRTROL VALVE eliminates a great deal of plumbing hassle with trapped air and sore knees.

BEFORE YOU DO ANYTHING please order these books from the heating help bookstore as they will save you a great deal of work and worry and headaches and your repaired heating system will work without being hampered by the air bubble menace.

Mr. Holohan has written these fine books with great care and he makes his reading fun and talks about hot water heating and its plumbing history and he writes plainly and simply making it easy for the lay person-you and me to understand as well as the journeyman plumber showing you how to spot a problem and or correct it for easier heating.

I would talk to a Bell and Gossett reseller and bring the pictures and explain that you want the simplest easy to manage air removal system which is the Internal Air Separator (IAS), steel compression tank, tank gauge glass, and ATF-12 Airtrol valve sized for your heating system and have them shipped to your home from a B+G reseller.

After 50 years Mr. Holohan still has his steel compression tank in the ceiling above the boiler at his home and it still works silently and makes no noise.

I would not hazard to guess how much you would have to spend but I saved a lot of money 8 years ago by purchasing almost everything I needed before the clown car plumbers I hired even started on my job.

The plumber can bring the wiring up to code as long as they know how to do it correctly as a plumbing inspector will look at everything and if it is not right it will be red tagged.

Read the three books I have told you about and then take a few steps forward and then decide if you want to make a decision tree to compare air control methods to maintain the point of no pressure change to assure your system is working correctly.

You could order everything like I did and have it shipped to your home and then you could buy the pipe, fittings, isolation flanges with gauge ports, American made Dwyer vacuum and pressure gauges for the isolation flanges, 2 ball valves to isolate the circulator from the piping above and below the boiler, a Dwyer Mark II manometer and probe and have them all on hand prior to the starting the work.

Some folks are going to disagree with me about this but what you want is simplicity and what I have had installed works, is silent and I no longer have to crawl around on my knees to bleed air from baseboard heating and as I mentioned Mr. Holohan's air removal system has been working for 50+years so....

If your high limit water temperature is only 120 degrees if the gauge is correct you can raise the high limit of the boiler to 150 degrees if you know how to adjust the triple aquastat.


I have sent you a PM.

neilc

unless there's a air/bladder tank there somewhere, those auto air vents should be capped down tight, you don't want them open with a ceiling tank,

and the fin tube, someone else mentioned it, the fins have an open side, and the side you have facing up and down with the 90 bend on it, the 90 bend should be front and back, not up and down like yours, and then of course the front cover,

leonz

There is no copper going to a bladder tank. Apparently the only air control device is the large automatic air vent you see in the picture.

hot_rod

It looks like a converted gravity radiator system with some fin tube add ons? Something odd about the diverter hood on the boiler also. Either it over-heated or the boiler on that high mass system is condensing and corroding the flue near the boiler?

It does need some TLC. I don't see an air purger or expansion tank. Possibly the radiators with some air trapped in them are acting as the expansion tank.

I'd guess that fin tube has been installed wrong since day one. It will still move some heat.
Hardwood flooring has closed off a lot of the air space needed for convection, a good portion of the fins are damaged. Time to replace the whole piece, move it up an inch or so, and make a better transition to the sheetrock work that is going on

I think you have a salvageable system. At the least it needs an air sep move the pump to the location of the air sep and expansion tank and air problems become less of an issue.
I would also add a boiler protection valve as you have a lot of volume and mass in a system like that.

There is a line cast into those balance valves stems sometimes. If it is inline with the piping it should be wide open.

rick in Alaska

Also,try lifting the section of baseboard that has the vent on it to see if you can get it a bit higher then the right side. It might be just enough to get air to the vent.
Rick

HVACNUT

Expansion tank in the attic?