Potterton heating. What ideal temp for boiler & cylinder

[Scarum]

Hi

I thought I had a problem with the Potterton "Suprima 30" boiler as the heating would not come on all the time (possible PCB jobber). I checked around and tweaked the temperature guage on the boiler itself and the temperature guage in the airing cupboard to the cylinder hot water tank.

As soon as I cranked the guage to hot water cylinder up from 55 degrees everything kicked into life!

Not sure how the guage was set this low (perhaps when I last decorated the bathroom this year) but wondered what is the correct or ideal temperature for this and for the boiler? And perhaps some kind soul can explain how they all interact?

Thanks.

 

[gas4you]

Standard temperature for the HW cyl stat is 60C. Higher than this will make scale form extra fast if you are in a hard water area, a lot less than this, say 40 -45C will promote breeding of any bacteria eg legionella in the stored water.

60C kills off these germs (if present)

 

[Scarum]

Nice call Dave. I had it up to 75 degrees for 15 minutes so thought I'd drop it a little

But when I did so and with the hot water turned off at the timer, the boiler stops and as such the central heating stops.

Perhaps the timer is broke?

 

[gas4you]

Could be the 3 port valve head or the ch 2 port valve is broken. Do a search on here for detailed advice on how to check.

I take it you have got the room stat turned up and calling for heat

 

[Scarum]

 

[Agile]

Nice call Dave. I had it up to 75 degrees for 15 minutes so thought I'd drop it a little

But when I did so and with the hot water turned off at the timer, the boiler stops and as such the central heating stops.

Perhaps the timer is broke?

That implies the calibration of the cylinder stat is incorrect.

They are often inaccurate! Try to get a temperature meter can compare the temperature with the switching point.

The main fault as Dave says is probably the three port valve is damaged. May need new motor or head.

Tony

 

[baxpoti]

Assuming you have a roomstat set at approx 20°C.

The SE Suprima should be run at max (82°C).

Optimum cylinder temp is 55°C with the stat placed ⅓ overall distance from base of tank

 

[Scarum]

It seems the 3 port valve is faulty, manually switching to CH starts the boiler but that soon stops.

The valve is a Myson MPE322. Can anyone please advise on the procedure to replace it?

Cheers.

 

[Scarum]

Well I whacked the valve and seems to be running OK now.

I found http://www.myson-htg.co.uk/install/MPE222228322.pdf which gives a guide on installation. What I wonder is if the motor of the entire valve faulty. Can I replace only the motor alone or must it be the valve as well?

 

[Agile]

The motors almost always fail o/c.

Once failed they stay failed.

Wacking it tends to confirm our expectation that its a faulty microswitch.

If so then that means changing the head ( if available ).

Tony