Baxi Boiler - violent vibrations - help

byzakman

New Baxi Solo HE 18kw - regular boiler ie. with existing hot water cylinder.

When working in water heating (only) mode and the return flow water temp. reaches within 8C of flow water temp. (flow = 73C and return = 65C) then the boiler violently vibrates and eventually shuts down with no alarms displayed. The boiler waits 15 secs approx and re-lights and the cycle repeats. The only way to stop it is to switch it all off. Baxi say its air in the system, the installer says thats nonesense and that the boilers faulty. I am stuck in the middle with no hot water!

Does anyone recognise the symptoms of the problem, is it a known Baxi boiler problem, any help/advice would be appreciated

bryanb

Before I read your post I guessed "air" from the title.

bambibashercol

Yeah it sounds air locked to me. I would get your installer to fix it. If you call baxi in for a repair and its not a boiler fault then they will charge you.

vaio

Hopefully the installer supplied and fitted the boiler and so it’s all his problem to sort out.

If not then you need to get Baxi out and if it is an installation/commission issue then, armed with a report from Baxi you can try and recover the costs from the installer.

DVardysShadow

Air is a possible. The other thing which can happen is that inside the heat exchanger, the water immediately next to the metal can reach a temperature where it can flash off to steam - along the lines of a singing kettle - but if it occurs to a more than trivial extent, the bubbles join up and stop more water coming on to the inside heat exchanger metal surface, at which point the water remaining in contact will also very quickly flash to steam.

Is the water heating circuit pumped or gravity? If it is pumped, you can try setting the pump to a higher speed.

Canucklehead

Hi.

Was an auto bypass fitted ? Or the h/w circuit has a valve on the return that is turned down too far. I take it the noise does not occur on c/h at all?

GSR.

EliteHeat

byzakman wrote: »

New Baxi Solo HE 18kw - regular boiler ie. with existing hot water cylinder.

When working in water heating (only) mode and the return flow water temp. reaches within 8C of flow water temp. (flow = 73C and return = 65C) then the boiler violently vibrates and eventually shuts down with no alarms displayed. The boiler waits 15 secs approx and re-lights and the cycle repeats. The only way to stop it is to switch it all off. Baxi say its air in the system, the installer says thats nonesense and that the boilers faulty. I am stuck in the middle with no hot water!

Does anyone recognise the symptoms of the problem, is it a known Baxi boiler problem, any help/advice would be appreciated

From cold, how long does it take to reach 73C and how do you know the exact temps? particularly the return.

penrhyn

Sounds like the boiler is kettling which should not occur on a new system.
Was this a replacement boiler for an existing system, if so was the system powerflushed and filled with inhibitor by the installer?
Is there a thermostat on the hot water tank?
There may be a bleed valve near the pump which you could try opening to check for air.
If there is any in the radiator circuit then trapped air would be shown up by a cool radiator.