baxi bermuda 552 back boiler no hot water , please help!!

20 Dec 2008
Reaction score
United Kingdom
please help , our old baxi bermuda back boiler has stopped producing hot water but the radiators are all heating up fine, the boiler has been well serviced and ive never had any problems before. The central heating is pumped but the hot water is gravity fed , any ideas? And if so how can i fix it ? also the boiler itself seems to be working fine - but only cold water is coming from taps?
Sponsored Links
Chec header tank in loft ball valve is probably stuck and tank empty
air lock in the primary circuit (to the cylinder) or possibly a blockage, can you check if the system is fed from the bottom pipe at the cylinder coil? if so you could part drain the system to see if the header tank refills which will confirm no blockage
Sponsored Links
coil in cylinder airlocked.
is the flow to the cylinder hot and return cold ?
the pipe going to the cylinder feels slightly warm , (warm at boiler getting colder towards the tank) does this make any sense?
if this is an air lock what is the easiest way of getting rid of it? i have tried running all the taps but nothing has changed?
depending on how pipework is done there may be an air release point at the top pipe of the coil, either a screwdriver or rad bleed key will release the air
the taps are on another circuit to the cylinder flow/return.

it should be hot at the boiler. not just warm
Possibly 3 Way valve sticking? I had the opposite problem a while back (hot water but no heating!)
ive just checked and there doesnt seem to be any bleed valves on the top pipe, any other sugestions?
sorry to be a nuisance.
I had a problem like this some time ago and eventually found a bleed point under floorboards in bedroom, above where the boiler was fitted, although this is pretty rare!
Usual cause of a gravity hot water circuit stopping is lack of water in system .
You say the header tank is full ,just to make sure cold feed is not blocked with heating off bleed the upstairs rads and make sure any air comes out followed by water.

If all is ok there .

It will be one of 2 things
airlock or worst case scenario coil blocked with sludge.

To remove air lock try turning boiler stat up to max with just hot water on, this sometimes shifts it but it will prob need boiling up which requires the removal of the thermostat phial from its pocket in the heat exchanger which by removing fire front on a 552 can sometimes be reached from the side without the need to disturb any gas connections which would require you calling someone in

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links