bAXI BERMUDA BACK BOILER NO HEATING

[suluki]

I have a problem on a Baxi Bermuda Back Boiler System as in that i get hot water when called for but don't get any heating. The boiler will fire up for about 15 seconds then cuts out back to pilot.

The hot water side is gravity fed with 28mm pipe. The heating side is a pumped system and fed in 22mm pipe.

Checked pump, working fine, also checked spindle inside pump and found to be working. On feeling the pipes from the pump water can be felt flowing. Their is no heat at the inlet or outlet side of the pump but as already stated water can be felt flowing through the pipework.

Checked roomstat and voltage feeding roomstat ok.

I am left with 2 possible problems:

Zone valve Knacked or an air lock in the system.

Looked every were for the zone valve but cant find one including the tank area. Anyone know where i might find it, will it be located someplace near the pump?. As i understand it some systems are not fitted with a zone valve?

Could it be anything else causing the problem?

Many thanks

 

[kevplumb]

zone valve

remove the pump

 

[ChrisR]

to locate zone valve. follow the wires. Often under the floorboards!
Thermostat on HW tank would indicate zone valve. Were the slots in the pump's impeller clear? ALso possible that impeller spins on the shaft or has come off - would still make noises and vibrate.

 

[suluki]

Their is no sign of a cylinder stat or wiring and water can be felt flowing through the system at either end of pipe on pump. I am thinking it could possibly be an air lock it the system.

On this kind of system what is primary the hot water or the central heating, bearing in mind that the pipwork for the water is in 28mm and the heating 22mm.
thanks

 

[kevplumb]

boilers working on gravity hot water but no heating
the pump is fine but cold both sides

 

[doitall]

Heating side of boiler scaled up

 

[kevplumb]

howay D I A

baxi bermuda back boiler

 

[doitall]

howay D I A

baxi bermuda back boiler

has 4 tappings so why not

age would be a clue

 

[kevplumb]

CURLY HELP
hes getting at me again

 

[bripl]

depends on age could be pcb,or the pump is useless not much else can stop abbu more than likely external controls

 

[suluki]

Well the boiler is about 10 years old.

initially the bbu had sooted up and after cleaning out found the burner tray to the bbu was split so replaced.
But the history of the heating side is that it had never fully warmed up the radiators for years, the rads only get look warm but the hot water is ok.

The boiler will fire up for about 15 secs then cut out as if the pump isn't working but like i said the pump seems fine. Well puzzled

( for the hard of understanding), The pipework both sides of the pump when calling for heat are cold but water can be felt running through the system.

 

[kevplumb]

for the extremely hard of hearing
if the boiler is firing and the hot water is ok the pump aint working or there is a valve closed

 

[bripl]

injector tee could be blocked so no circulation would explain why the poor performance,maybe the oap has a point about 5hite in the heat ex

 

[doitall]

injector tee could be blocked so no circulation would explain why the poor performance,maybe the oap has a point about 5hite in the heat ex

Why thank you bripl

 

[bripl]

no prob oh wise one