Hot water but no heat to radiators.

[simonhamnett]

Hi, I'm new to this group and I hope there are some experts out there who can help.

Boiler - Baxi Solo 2 40PF
Drayton Mid position 3 port valve

Problem. House left empty for 2 weeks boiler - OFF
On start up - Buzzing sound from boiler.
Boiler starts and we have hot water but No heat to radiators.

Should the two pipes from the mid position valve ( MPV) both be hot when the controler is set to CH only ?

If I manually ( not otherwise ) set the MPV I can get hot water to the radiators, but also hot water.

Is my MPV faulty ?

Many Many thanks for your expert help.

 

[Hugh Jaleak]

Answer is no, only central heating pipe should get hot with system set for heating only. If you open the MPV manually then both circuits will get hot, the valve motor is overridden and allows water to exit through both ports.

Before condemning the valve I would (if you are competant!) check there is power coming to the valve when roomstat is calling for heat.

 

[simonhamnett]

Thanks for the reply Hugh. I'll check that.

Anyone know why the system should play up after being off for two weeks, and why I get the buzzing from the boiler on start up ? I did read that a faulty MPV can cause a Baxi Solo to buzz ?

Many thanks.

 

[DP]

You might have two faults on your system.

Motorised valve/ controls make a demand on the boiler. Boiler then goes through operate sequence to fire the burners and heat primary water. If boiler noisy then investigate boiler noise. If no water to rads, then investigate controls. Simple as that.