I have an older WM boiler (CGi model) with 4 zones coming off it. All zones work great except my basement zone which was added last. This zone seems to work for a while and then it will not... when that happens the pipes never get hot or only a short distance form th eboiler gets warm and goes no further. There are several differences with this zone compared to the 3 others. One, I believe the piping has a longer distance to run, two the piping is a black plastic-like material because it had to move up and down in the basement (I did not have this done but inherited it with the house) and it is smaller diameter than my other heating pipes. Also, the zone does not have the same flow valves (is that what they are called?). My three working zones all have Taco 220 Universal Flochex on their lines while the basement zone has a smaller contraption called a Taco 219 Swetchek (if I read it correctly).

I have had several heating guys look at it and the first thing they all suggest is air in the line. However, we have bled it again and again and that does not seem to be the problem. Another guy suggested a crimp exists in the plastic tubing which I agree could be the cause it but does not explain why it will work for a week and then not at all.

I read something on line that talked about a series of older WM boilers that have a flow re stricter built in and they were suggesting this might be an issue for a guy who wrote in with what sounded like a similar issue as mine. This is what was written, "they have a flow re stricter built in that diverts 30% of water leaving the boiler back to the boiler in case there is ever a cold back serge of water entering the boiler. So the only way to make sure the water gets the push it needs we are going to have to install a second circulator on the piping manifold exiting the boiler before the zone valves. The nice thing is because of the zone box it can be wired directly to the extra end switch in there." Not begin a heating guy I am wondering why this would not effect other zones as well but this specific individual had one zone like mine in a basement that was not working properly.

So, before I have a heating guy ripping into my wall to look for a kink in the tubing that may not actually exist, I wanted to investigate the possibility that it could be one of these other things.

Any thoughts to speak to the next guy who comes to my house or things I could try on my own (I am not a plumber) would be appreciated.

The Taco 219 and the Taco 220's are flow preventers or like a check valve. They are so that when one zone calls for heat they don't all get hot water.


Is this a one pump system ?
Or are there 4 zone valves with wires on them.

You need to approach this logically. If you had a flow problem (not a big enough pump) then the loop where the water has to travel the furthest and highest would suffer first. That would most likely be a second floor loop although you indicated you thought the basement was longer.

If you had a loop made of plastic pipe and you thought that maybe it was kinked or restricted you would disconnect one end of it and see how much water came out. You wouldn't just go blasting walls open in search of it without proof it was really kinked.

My guess is that you have a zone valve that's not opening or opening all the way.