Kickspace heater not getting flow

jamesdinty

Hoping someone can help me. My kickspace heater won't turn on recently. It's been working fine for 20+ years and I haven't used it since last heating season. I noticed the supply pipe and return pipe are not heating up. This unit is plumbed off a main line and has shutoff valves on both supply and return sides. These valves are just beyond what appears to be a mono flow tee off the main lines. The valves also look to have a bleeder screw on them.

I suspect that there is air in the lines going to the kickspace heater but when I open the bleeders up nothing but water comes out (no air). It's most likely that I am not bleeding this correctly. Can someone let me know how to do it. There is clearly no hot water flowing through the kickspace heater and that's why it won't turn on.

Pics - Supply side


Return Side

Teemok

I'm assuming the main is hot and circulating. There is likely a coin vent on the heater itself. Air vents at a high point. Access can be hard. The caps on the ball valve are good for drain down. You must turn a ball valve off to attempt to get the air out of the heater loop. The one you turn off is the drain cap you open. You might try closing both ball valves taking the cap all the way off with a bucket under it and then open the other ball valve hoping air is pulled down with the higher flow. You can try this in both directions.

jamesdinty

Teemok said:

I'm assuming the main is hot and circulating. There is likely a coin vent on the heater itself. Air vents at a high point. Access can be hard. The caps on the ball valve are good for drain down. You must turn a ball valve off to attempt to get the air out of the heater loop. The one you turn off is the drain cap you open. You might try closing both ball valves taking the cap all the way off with a bucket under it and then open the other ball valve hoping air is pulled down with the higher flow. You can try this in both directions.

Thanks for the response....
Yes...the main is very hot and circulating. I can remove the floor of the kitchen cabinet that exposes the top of the heater but I don't see any vents on the heater when I do that. Could be hidden from me though. Am I stuck unless I can find that vent on the heater? Or is the second part you mention about getting the air out of the heater loop still worth pursuing? If so....should I

1) Close both valves
2) remove one of the caps and drain into a bucket
3) open the opposite valve

then repeat the above in the other direction?

Do I have that right?

EBEBRATT-Ed

Yes, that method might work but there is usually a vent in the heater. If it worked before it should work now. What is your boiler pressure? do you have 12-15 psi?

Do the pipes to the heater get warm at all or are they cold?

EdTheHeaterMan

First look for a vent at the top of the heater. see the illustration

if not then do the other thing below.

jamesdinty said:

1) Close both valves
2) remove one of the caps and drain into a bucket
3) open the opposite valve

then repeat the above in the other direction?

Do I have that right?

Yes that is correct. However that opening in the valve may not have enough volume to force the air out of the radiator and DOWN to the opening in the basement/crawl space

You will want to get the boiler pressure up to about 25 PSI before you try that. That way you will have a better chance of forcing the air DOWN to that vent.

Teemok

That B valve is closed when you open the A valve to purge air out of the removed cap at B. The cap has to go back on without letting air in. Alternative fault: Mono flow T's can clog, I guess. Rare I would think. System pressure check is a good call Ed.

jamesdinty

EBEBRATT-Ed said:

Yes, that method might work but there is usually a vent in the heater. If it worked before it should work now. What is your boiler pressure? do you have 12-15 psi?

Do the pipes to the heater get warm at all or are they cold?

Ok, I'll open up the cabinet floor again to look for the vent as a first step now that I know where to look for it. The pipes to the heater are all cold but the main pipes are hot and the rest of that zone is heating just fine. So it's just that kickspace heater loop that is cold.

Boiler pressure is reading 20psi

jamesdinty

EdTheHeaterMan said:

First look for a vent at the top of the heater. see the illustration

if not then do the other thing below.

jamesdinty said:

1) Close both valves
2) remove one of the caps and drain into a bucket
3) open the opposite valve

then repeat the above in the other direction?

Do I have that right?

Yes that is correct. However that opening in the valve may not have enough volume to force the air out of the radiator and DOWN to the opening in the basement/crawl space

You will want to get the boiler pressure up to about 25 PSI before you try that. That way you will have a better chance of forcing the air DOWN to that vent.

Thanks for the picture....I'll look for that vent. If I find it, should I just open it up while the heat is running?

jamesdinty

Also, if I can't find the vent on the unit, I'll try the other procedure. To raise the pressure from 20 to 25 psi, do I just let more water in? Then after the procedure, how do I get the pressure back down to 20 psi (which I assume is my normal operating pressure).

jamesdinty

By the way...I appreciate all of the great info from everyone. Sounds like I should be able to get this thing working soon. It must be either air in the loop or a clogged mono flow tee. I hope it's air cause I will have to call a plumber to change out the tee

jamesdinty

SOLVED......

Turns out the unit vent was strategically located right on the front panel with a rubber tab placed over it. Put a sheet pan under it, pry off the tab, unscrewed for a few seconds and voila! Thanks again to everyone for making me look again for the unit vent.