No heating

[Trikster4181]

Good Morning all,

Im hoping you can help, we have been in our new house nearly 6 months and everything has been perfect until Sunday, We woke up and the house was cold.

The system is a Rayburn powered by oil, this does cooking and heating/HW in the kitchen, through in the Utility room there is a cupboard with a pump. From the pump the pipework splits to 2 x drayton ZA5 a Actuators (one marked HW and one marked heating)

All the pipework is really hot to touch, as is the pump but the pipe coming out of the heating ZA5 is cool, so i think its pretty safe to assume this is my problem. I have 3 questions though.

1) does the ZA5 tell the rayburn when to switch on, as when i manually put the heating on via the programmer the rayburn remains silent and doesn't appear to kick in (the cooker side works perfectly though)

2) As a man with very little DIY experience or confidence is it an easy fix to replace the ZA5?

3) In the short term can i just move the manual switch and basically jam the system on?

Sorry for long post, trying to avoid a huge plumber bill. Thanks in advance

 

[jackthom]

Does the hot water ZA5 fire up the Rayburn and the pump ok?

You should be able to get the heating going in the meantime by locking the heating ZA5 manual lever in the open position. When open, a micro switch inside the valve normally switches on the boiler and pump.

 

[stem]

1) does the ZA5 tell the rayburn when to switch on, as when i manually put the heating on via the programmer the rayburn remains silent and doesn't appear to kick in (the cooker side works perfectly though)

Inside the motorised valve is a microswitch that when the valve winds open it normally switches on the boiler. How this works with a range / cooker I'm not sure though because it is kept hot permanently. Possibly it just controls the pump.

2) As a man with very little DIY experience or confidence is it an easy fix to replace the ZA5?

Yes the head can be replaced without draining the system. An internet search will provide you with instructions and the part that you need.

3) In the short term can i just move the manual switch and basically jam the system on?

Possibly, depending on how your range operates. Whilst the lever will manually open the valve, it doesn't normally move it far enough to operate the microswitch and maybe not start the pump.

It sounds most likely that the ZA5 is the problem, but it might be that the room thermostat is not operating it. This is far less likely but it can happen, especially if the room thermostat is battery operated.

 

[Trikster4181]

Brilliant thank you. This may sound daft but im sure we done have room thermostats, just old fashioned radiators with settings on the inlet.

In my opinion the ZA5 must also be telling the rayburn not to make any more hot water. Im half tempted to go to screwfix and but the ZA5 myself and save a few quid.

Thanks again

 

[Trikster4181]

Sorry Jackthorn i didnt see your post, Perhaps locking it into manual tonight would be a good test, also if i run the hot water long enough to trigger the pump and boiler to make sure that side of it is working.

Im not sure why but when the previous owners installed the system they went for a power shower when surely a mixer would have worked better as we have a 5 foot tall hot water storage tank and we need to run alot of hot water to get the system to kick in.

 

[jackthom]

Apart from looking at the indicator on the valve, when the heating is supposed to be on you should find the za5 manual lever easy to move if the valve has already opened. If there is some resistance and the lever springs back to the closed position there is a problem with either the ZA5 valve motor or the electrical feed from the controls going to the motor ( possibly a programmer or room thermostat problem)