Potterton PTT2 noisy - clean? faulty? replace (seems impossible!)

[dubmuffin]

Hello, can anyone help?

Our old house is now rented out and the PTT2 Themostat, which has always chattered a bit if it is in limbo between below and reached, has become very noisy, the chattering is now more shouting and it is causing the tenant some concern. If I still lived there I'd probably put up with it but I need to check why it is doing this and if it is going to cause any problems.

I'll always try a repair before a replacement, but the replacement option doesn't look straightforward, and when I open the case it's just wires and a pcb, so doesn't look serviceable, any advice?

Thanks
Claire

 

[CBW]

Could just be old and might just want replacing, it’s only a thermostat, not much to it.

 

[jeff the gasman]

Get it replaced before it starts a fire.

 

[dubmuffin]

What should I replace it with? They don't make them any more, it's external, not one that sits on the cylinder

Why would it cause a fire, surely the RCD would trip first?

 

[Rodders53]

https://www.diynot.com/diy/threads/potterton-ptt2-equivalent-replacement.490316/ is a relevant older thread on this obsolete thermostat.

If in doubt of ability to diy call in someone to replace it; especially as it is tenanted.

 

[CBW]

What should I replace it with?

Quite literally loads of thermostats that could replace it, depending how it’s been wired.

 

[dubmuffin]

It would have been wired like this:

Installing and Wiring a Potterton PTT2 Cylinder Thermostat

Faced with this problem I found lots of confusing and incomplete information on various sites. So this note gives the benefit of my experience in getting this cylinder stat working. Most commonly people will be replacing a bi metal mechanical thermostat which sits on the cylinder with this...

www.diynot.com

 

[CBW]

It would have been wired like this:

Installing and Wiring a Potterton PTT2 Cylinder Thermostat

Faced with this problem I found lots of confusing and incomplete information on various sites. So this note gives the benefit of my experience in getting this cylinder stat working. Most commonly people will be replacing a bi metal mechanical thermostat which sits on the cylinder with this...

www.diynot.com

Apologies, thought it was a room thermostat (Googled it). There’s still quite a few it can be replaced with.

 

[jeff the gasman]

What should I replace it with? They don't make them any more, it's external, not one that sits on the cylinder

Why would it cause a fire, surely the RCD would trip first?

https://www.ephcontrols.com/wp-content/uploads/2017/05/20180627_CDC_InsIns_JW.pdf

 

[jeff the gasman]

What should I replace it with? They don't make them any more, it's external, not one that sits on the cylinder

Why would it cause a fire, surely the RCD would trip first?

If the chatter comes from a load carrying relay the arcing can cause a heat build up.
Not low voltage contacts.

 

[dubmuffin]

Thanks for all the info. I've been to have a look and took the over off. It is very dusty inside and outside (the tenants just don't really do cleaning of anything!). There is some sooty staining on the inside which makes me think heat, but it wasn't making the noise when we tested it. They try and get by on only solar water heating all summer so it only gets used (or noticed) about now each year, so it's been dusted and I've booked an engineer to test it. It's good to know there is a replacement, (currently out of stock though).