Problem with potterton 100l boiler

[FrankieF]

Hi people,
I have a problem, and hope you can help me with.
I have a Potterton suprema 100l boiler, and can only get hot water when I have the central heating on too, I cannot get hot water only.

Can anybody help me? with many thanks.....

 

[plumbnuts]

Hi
I don't know how much you understand about heating systems, if you need more help, then please ask. Do you have a 2 x 2 port diverter valves or 1 x 3 port?
Steve

 

[FrankieF]

Hi,
Thanks for responding....

There are 2 x 2 port valves, and when I set thermostat and programmer to call for heat, the valves did not move, or when called for hot water, they didn't either, they seem to be stuck. They do look old and the spring looks like they have not moved for ages. The switch also doesn't seem to be fully closed either. I am sure these must be the problem, but would like to be assured, so would appreciate any response.
Can I replace the curcuit and housing, or do I have to replace the whole valve...?
The boiler seems to work okay, as fires up if call for hot water or heating.

Thanks.

 

[plumbnuts]

Hi
You cannot always see the valves move. With the heating and HW off, the lever on the end of the valve should be quite stiff and if pushed accross against the pressure of the spring, it should return to it's original position when released. Try this first and the turn on the heating and HW and check the levers, they should now be easy to move with little resistance. The motor is normally the problem and is easily replaced, let me know and I will tell you how to change it.
Steve

 

[FrankieF]

Thanks Steve, you have been a great help. Unfortunately, the system is a friends, and cannot look at it again for a few days, I hope that when I do get a chance, that you can still help me afterwards...
Really appreciate the help, I am an aspiring plumber, and have just passed my C&G Level 2, and with your help will go onto learning a great deal more.

Thanks again....

Fraser

 

[FrankieF]

Hi,
I've been able to look at the valves now....
The switches are not moving and stiff even if the hot water or the heating is on or off, so I assume the the whole of the valve is knackered and may have to replace them completely, what do you guys think....thanks.

Fraser

 

[Mike Jackson]

I'd take the valve heads off and try with a spanner on the spindle, if they're stiff time for complete new valves.

Mike

 

[Bernie2]

I suppose it depends on a couple of things.

1. How is cash?

If you have got a decent wedge, replace the valves.

2. If skint?

Turn of heating, drain down (got to do that anyway) remove valve, disassemble, inspect, if okay, just bunged up with rubbish, clean, grease and replace, try, if moving freely, try motors, if faulty replace. Then run and check for working any leaks.

If you have got a multi meter you can test the Ohms resistance of the motor to find out what state its in.

You can also I think buy repair kits for some makes.

Its amazing what old crudded up parts will work for many years after a bit of maintenance.

I rescued a c/h pump Myson unit five from a trip to the skip about 10 years ago and put it in a system. Still going.

Don't forget we live in the age of the Wombles, let's recycle?

Okay so you don't want call backs for using recycled stuff!! Tell the customer what your doing and charge less, give a short guarantee, they might think its a good idea.

 

[FrankieF]

hey guys, i'm back with the same problem.

I have now replaced the two-port valve, and the system still has the same problem, the only way for the cylinder to get hot water is to have the heating on......
it seems, that when you call for hot water only, the boiler does not kick in, unfortunately, this means there is no hot water, but if you put the heating on too, then we do get hot water....

Could this be a problem with the cylinder stat, or the programmer then...?

I hope we can resolve this problem...thanks again....

Fraser

 

[Puddle]

Well,you have replace hot water valve so we can assume new valve not by passing
therefore if you get hot water when heating on we must also assume hot water valve is opening,as new the micro switch that sends power to boiler should be ok
Therefore would think problem with gray or orange wire connections in wiring centre.
With heating operation correct these wiring connections should be correct.
Check your hot water valve orange and gray wires are connected to the same terminals as the heating gray and orange wires,maybe one loose,if ok
remove hot water valve head and make sure opening with demand
Failing above the you are going to get into checking power run from programmer to valve via cylinder thermostate

 

[FrankieF]

well, the boiler kicks in when the programmer/heating asks for it, but if the programmer is set to only bring the hot water on and no heating, the heating valves closes, the hot water valve opens, but the boiler does not fire up......which leads me to think that the cylinder stat, may not be asking for heat, and the cylinder will only get the heat from the heting curcuit.....the cylinder stat look quite ancient.....does that help....

 

[Puddle]

If hot water valve is opening when hot water set to demand on programmer then cylinder thermostat ok as power must pass through cy stat to power valve through brown wire on valve.thus cylinder stat must be calling for heat for valve to open.
Power to boiler is from orange wire from valve when opened via gray wire which should be connected to permanent live ,supply this sounds like the problem area,gary or orange connections or micro switch in valve but as valve new this should be ok