Had a half S converted to S, now Cylinder issues.

[RobBob]

Hello. Skip to the last paragraph for the round up

I'm sorry, I'm new. I did search but i'm not completely sure of the terminology around what I'm asking.

Skip to the last paragraph for the round up - but the back story is....

We moved in this summer (bet you've all heard that before).. the heating system is no spring chicken, but it seemed to function as it should for the way it was designed. - Boiler in Garage, pump in cylinder cupboard on 1st floor, before it hits any valves. Immediately after the pump a pipe went off to the CYL flow (as in, how the boiler water gets in to the tank coil, I think that's the flow?).. a valve after this junction then allowed the water from the boiler to also go around the radiator circuit.

We had no CYL stat, so I started to think we should have the system altered to allow independent control of the W & H, and fit a cyl stat. Our programmer is only a couple of years old and has the capability to do this.

So - The programmer was re-wired as required, a CYL stat fitted and the room stat replaced (was very slack).. Control wise, we seemed good.

We also had the 2 way valve replaced with a mid-position divertor valve along with the pipe work modification to do so.

All seemed well after an initial hicup with the valve and now I can turn on Water, Heat or both from the controller and the stats switch the valve to and throw as expected... - Great.. Well, almost.

Having converted the "not quite an S system" to a Y system the CYL has a permanent trickling sound on the coils exit pipe, it's minor when running H&W but when the system is switched from H&W to just W there's a huge noise of moving water and air and the trickle is louder. If you whack the pump on to max it seems to push most of it out of the system but i can't leave the pump on max because when the heat comes back on it start shooting heating water in to the header tank. I've tried bleeding the CYL but it doesn't seem to help. The heating is working fine but I suspect the HW isn't heating up as much as it could be as it takes a few hours to click the cyl stat off at 55'

Any help with this would be great, I'm sorry it's a bit vague. Please ask me any questions that might lead to a solution.

 

[Riley]

Sounds like air

 

[RobBob]

Thanks, I'll have a better go at bleeding it tonight. Just seems odd that I can almost completely clear it with the pump on max but then, soon as H&W switches back to just W there it all is again.

 

[RobBob]

Hmm.. Just pondering. When I initially bled the coil, the exit flow has a radiator style bled valve, which seems to be working.. But the incoming flow to the coil seems to have a screw on cap with a hole in it.. Is there an sharder valve hiding under there possibly? I haven't taken it all the way off because the first time i loosened it black water weeped from the hole... Since then, nothing comes out when twisting the cap and now I'm wondering if ive been stupid and it's a sharder valve.

 

[doitmyself]

But the incoming flow to the coil seems to have a screw on cap with a hole in it.

Can we have a pic of this valve?

 

[SimonG]

Sounds like a mix of air and incorrect plumbing if it's pumping over.

 

[Riley]

I think the Schraeder valve you are referring to will be a thumb air valve