pump fails to start

[nigelw]

my daughters potterton ultima? 30 boiler starts and heats hot water but the pump does not start so no central heating. it has a three way valve in the system. There is no power either at the pump or at the pump live terminal on the boiler. the CH neon on the three way valve lights up if the potterton programmer has CH turned on. room stat is turned to max.

only other comment here is that in hot water only mode it cycles a lot.

any ideas?

 

[boxster]

hard to say unless your at the job. go to the fuse box and look for CH or anything close top that, if you have a mulitmeter check it. remember a neon can glow but it doesnt mean 240v is there. A pump needs that power to work. Take the tope of the pump off and smell it... if it stinks your pump caused the blow. swap the fuse with a replacement in the box.

it all depends on how your system is wired up. the CH fuse may be only feeding a spur and pump. if there is no power to the pump a wire may have also come loose. you have check for power at the clock? and pump? and boiler? nothing there check the MAIN board for any fuse that is blown regardless of what it says as it may have ben swapped before

 

[oilman]

Is the three way valve a motorised valve? If it is I would guess at that being the problem, they fail frequently.

 

[boxster]

i aint sure oilman there is no power at the pump or pump live, somethings caused a short, my money is on the pump, flip the cap if it stinks like a burnt plastic smell replace it. I remember i did an apollo and the house was a dump i mean rubish on the floor, hell even dog cocked its leg and wet against the fridge, it was stinking.... the same problem apart from the pump overrun blew! replaced it and bingo, not the same here tho

 

[nigelw]

i should have said its not the pump. i replaced it yesterday before checking the supply - dumb eh! - i'm pretty sure it is a motorised valve, so will consider this potentially faulty. what about the room stat? should i by pass this? also, what about the PCB, or a component attached to it? could this turn off the pump live?

 

[boxster]

If you have no power to the boiler the problem lies elsewhere. When you check the LIVE you are checking witha multimeter and not a neon? A neon can still glow at low power and the boiler needs 240. The reason people like me and other gas engineers hate neons is it can say its working fine when infact its not.

are you getting power to the fuse spur?
are you getting power at the clock or timer?
are you getting power at the boiler?

I cant see how it can be a valve as its a long shot for no power at the boiler live. maybe it might have caused it... but i dont think re-newing a valve may fix it.

also room stats have been known to blow the boiler. disconnect the room stat from the boiler, then replace any fuses and try again, room stats can cause this..

best of luck

 

[nigelw]

thanks for this lot guys. the boiler is working and heating hot water, so there is power to it. the programmer is also working. just the pump which appears not to be getting any power. i will start at the fuses and work my way up. thanks for all the advise so far

 

[boxster]

yer check the fueses