Mysterious air block/blockage somewhere in CH system

[Pallatrax]

Chaps,

I wonder if you can help please..

I visited a friend last weekend and topped up his combi after he bled the system to the extent the boiler lost all pressure. This came about when he tried to get some heat in a towel rail that previously had only ever got warm around its base...

When I left it was nice and toasty but apparently since then it has refused to warm up despite all the rads being nice and warm around the house.

He has (reportedly):
Closed the rads off upstairs to try to force water around the TR
Bled every rad and got no further air out
Checked boiler is on 1bar
Pressed 'boost'
Promised me the valves are open on the bottom of the TR

Is he (or I for that matter) missing something? I don't want to travel to see him if he needs a plumber, but I fail to see how it can be anything of a serious nature!?

Thanks in advance

Regards
P

 

[Pallatrax]

16 views and no replies - no one care to take a guess or are ya too chicken?


P

 

[oldbuffer]

Impossible to tell for sure without being there, but consider:

a) Duff valve on towel rail
b) Towel rail is a "designer" job which requires correct flow / return connection
c) Towel rail is on hot water circuit, not CH
d) Towel rail has sludge in it

 

[Pallatrax]

Impossible to tell for sure without being there, but consider:

a) Duff valve on towel rail
b) Towel rail is a "designer" job which requires correct flow / return connection
c) Towel rail is on hot water circuit, not CH
d) Towel rail has sludge in it

Thanks for your input Oldbuffer - much appreciated

The TR got hot when bled BUT could be on hot water circuit!!!! Hmmmmmmm!

Valves might be duff, but they're not thermostatic ones that i'd imagine are more prone to going belly up.

I suppose he could disconnect and run a hose through it!

P

 

[ChrisR]

There's no HW circuit if it's a combi.

A combi would check for a dud pump, others generally not.
Checked pump for air lock?

refused to warm up despite all the rads being nice and warm around the house

??

 

[Pallatrax]

There's no HW circuit if it's a combi.

A combi would check for a dud pump, others generally not.
Checked pump for air lock?

refused to warm up despite all the rads being nice and warm around the house

??

Now i'm confused.

A DIY plumber might of plumbed it into the HW pipes - that is what oldbuffer was getting at.

I'm not experienced enough to check pump

Cheers
P

 

[oldbuffer]

OP, ChrisR is quite right. If it is a combi boiler (no hot water cylinder) then the towel rail will not be connected to the hot water. My fault for not reading your original post thoroughly enough.

If however it is a sealed system (hot water cylinder but no feed and expansion tank) then it may have been plumbed quite properly into the hot water primary circuit, the circuit which feeds hot water from the boiler through the internal coil in the hot water cylinder.

 

[Pallatrax]

Hi,

There is definitely no cylinder, just combi on the ground floor - he just confirmed via text.

If the TR was plumbed into the feed to the hot tap it would get hot on occasions, but my friend is adamant it only got warm at the bottom, but did so every time the CH was on. This is until last weekend when i topped up his system, when it got nice and hot, only to fall cold again and not pick up since.

I'm leaning towards him being a numpty or it being a faulty valve i think!

Thanks
P

 

[joe-90]

I'd suspect he hasn't opened the lockshield valve. Bleeding the system will let water in to displace air - so it gets hot. Next time the water can't get in or out so just stays warm at the bottom.

 

[easyflow]

I would say at a guess that your friend fitted the towel rail himself and mad an error of connecting the flow feed to both valves, or the return feed to both valves !
Been to several breakdowns in the past where peeps have installed themselves flow or return on both valves.

 

[Pallatrax]

All fixed guys!
I popped around and set about removing the towel rail and once over the bath I discovered the valve at one end was not opening sufficiently. As it turns out these valves (new to me) are the type fully open when unscrewed only half way. They also have a lock nut and this was tight preventing enough movement to open it.
Obvious when you're a plumber I'm sure, but the chrome cover also has a spline but only on the one side - so the covers don't match despite the valves operating in the same way.
All toasty warm now!
Thanks for all your comments
P