What is going on with our boiler...?

mekondelta

We have a Potterton Suprima 60 boiler which we inherited with the house. Obviously no manual etc.

Now, it all generally works fine but since I've changed the settings it's been playing up.

I have the HW/CH on from 4:30pm to 11:30pm. At about 8:15 the boiler turns off and the red light comes on. The thermostat says that the temp isn't hot enough and so the boiler should be on. The timer says the HW/CH is still on as well. Anyway, at about 9:50pm the boiler will come back again and all is OK, ie the radiators heat up again etc.

Anyone know why it has a siesta between 8:15 and 9:50? It doesn't make any sense to me at all!

Any help appreciated...!

chudies

could be the "heating sensor"

cost is a tenner to replace, but requires fiddling around

i have a baxi boiler (i think they are sister companies with common parts)

basically boiler would cut off when it got too warm, and restart later

written this, but not a plumber

robowen

mekondelta wrote:

We have a Potterton Suprima 60 boiler which we inherited with the house. Obviously no manual etc.

Potterton were taken over in 1996 or thereabouts and are now called baxi potterton. You can obtain a manual for your potterton boiler by calling their after sales technical support on 0870 609 9049.... they will give you a phone number and if you quote your boiler make, the paperwork appears in the post within 3-5 days.

rob

qbatqbat

Suprima 60L?

If so, try this:
http://www.potterton.co.uk/products/literature/Potterton_Suprima_L_User_Guide.pdf

moneysavingplumber

These boilers can be a nightmare to diagnose when they go wrong. It could be the stat sensors, but it could also be the PCB, but if the boiler hasn't been correctly installed (i.e. 28mm primary pipe work upsized from the 22mm tails on 60,000 and above and a correctly adjusted auto-bypass) it could actually be overheating (technically) in some circumstances. I almost always changes stat sensors before PCB, as an erroneous £20 is far better than £140.

mekondelta

qbatqbat wrote:

Suprima 60L?

If so, try this:
http://www.potterton.co.uk/products/literature/Potterton_Suprima_L_User_Guide.pdf

Thanks. The Potterton site has been down the last few days and has only just come back up so couldn't get the manual.

Will take a look.

robowen

I just tried the link now and its working.
Try the link, if you cant get it pm me and I'll send over the copy I saved.

rob

edit
few more phone numbers for you :
General Enquiries :Tel. 08706 060 780
Technical *Tel. 08706 049 049
Service *Tel. 08706 096 096
Fax. 01926 410 006
Literature Request : Tel. 08706 060 623

mekondelta

Right, think I've got it sussed. The boiler was overheating, so I turned the temperature on the boiler down and it seems to be OK now. It was on maximum for 7 hours continuously before.

Shouldn't it be able to go on max all day?

moneysavingplumber

mekondelta wrote:

Shouldn't it be able to go on max all day?

Not if it's been oversized for your property, the primary pipe work has been undersized (which will eventually encourage limescale build up in the heat exchanger, further aggravating overheat problems), and the circuit isn't correctly balanced or by-passed.

If this boiler locks out at a specific time each day after several hours operation it's usually down to an overheat. If it sporadically locks out at different times flashing temperature, it's usually the sensors or PCB. If it locks out first thing every morning, it's usually a cracked spark electrode or a sticking gas control valve.