2 Port Valve Operating But Still Intermittent Heating- New to this problem

s3anreilly · Dec 22, 2016

Help appreciated to help me think this one through.. 🙂

Have changed the synchro motor

Gears are fine.. micro switch fully engages when hot water is switched on from timer.. you can see and hear the click from the microswitch

the switch is calling for the boiler to burn.. hot water no problem

Surely the microswitch, when off, closes the pipe to the cylinder and just directs the heated water into the central heating SO what triggers the call for central heating..maybe an open microswitch at the 2 port and a call from the room stat.

room stat is turned up

SO.. the room stat is faulty as the 2 port seems fine?

The heating sometimes works but sometimes doesn't.. an intermittent room stat fault?

It's an unvented system with solar water heating.. so two 2ports to the cylinder.

Last Plumber · Dec 22, 2016

You must have another two port for your heating circuit.
Programmer-Room stat-MV- Boiler on !
you need to check the heating MV Surely.

s3anreilly · Dec 22, 2016

Yes, there is a two port for the solar hot water heating

Thank you

Last Plumber · Dec 22, 2016

MV = Motorised Valve.
There are two or three port types in most domestic installations like yours.

You normally would have an 'S' plan ( zone valves or two port valves, one for each zone e.g Hot water, Heating upstairs, Heating downstairs, Underfloor heating etc).

Or a 'Y' plan which is a three port valve ( one port to Heating and one port to Hot water)

What set up have you got?

The thing you mention about open microswitch and signal/voltage from room stat is not correct by the way

s3anreilly · Dec 22, 2016

there is no three port.. with the cylinder are two two ports..

Last Plumber · Dec 22, 2016

A two port can't control two circuits separately.

Is it possible you have another one you haven't seen

Can you post photos of what you have got.

s3anreilly · Dec 22, 2016

found it.. there are three two ports

two are honeywell and the other is a danfoss.. pic here

so.. i guess this is the culprit? Guess Ii need to remove and check gearing, synchro motor and micro switch.

🙂

Thankyou

Last Plumber · Dec 22, 2016

s3anreilly said:
found it.. there are three two ports

two are honeywell and the other is a danfoss.. pic hereView attachment 28422

so.. i guess this is the culprit? Guess Ii need to remove and check gearing, synchro motor and micro switch.

🙂

Thankyou

I would check the voltages are correct (L+N) at the valve supply when there is a call for heat. Rather than pull it to bits. It could save you a lot of time and effort.