fuse blowing

[mat 60]

can any one help.
when i select heating or hw on an old style potterton ep2000 control the fuse in the wiring center blows.if i remove the earth wire from the control i can select hw and the fan starts but get no spark in the boiler.if i selct the ch nothing happens.
could the controler be faulty?any ideas as i am getting fed up of being ripped off by cowboys.

cheers

[jimbo]

This is a tough one because your description of the problem is a little vague. Without a wiring diagram of the devices involved, it is tough to advise, except it is not a good idea to remove any ground wires. However, that symtom may be very helpful to an on-scene tech. Unless you have some schematics and wiring diagrams to work from, I suggest you may need to call in a professional.

[Bill Arden]

cheers

"potterton ep2000 control" = low voltage controler.
Problem "the fuse in the wiring center blows if used"
Hint "If the earth wire from the control is removed the fan starts but get no spark in the boiler.if i selct the ch nothing happens."

From link below
# (R), Red, hot side of transformer.
# (Y), Yellow, Compressor activity (cooling or cooling and heating on a heat pump).
# (W), White, Heat (gas burner, oil burner , electric heat, (auxiliary heat on a heat pump including defrost output from the outdoor unit to activate electric heat and turn on the AUX. heat lamp).
# (G), Green, furnace blower fan. (needed for air conditioning, heat pumps and some electric furnaces). NOTE: on most thermostats the "G" and "Y" are connected together at all times when the fan switch is in the "Auto" mode, If you sully R to G then you will most likely energize the outdoor unit contactor!
# (O), Orange , Energize to cool (used for reversing valve on heat pumps)
# (B), Blue or Orange, Energize to heat (used on some systems, Rheem/Ruud is notorious for this).
# (C) (CC) (B) or (X), Blue, brown or Black, common side of transformer. Needed on some electronic thermostats or if you have indicator lamps. Do not confuse with (B) Reversing valve (energize to heat) above. York and Trane like to use (B) as common.
# (E), blue, pink, gray or tan, emergency heat relay on a heat pump. Active all the time when selected, usually not used.
# (T), Tan or Gray, outdoor anticipator reset.

I am asuming you are talking about the fuse for the low voltage wireing and not the breaker in the main electrical panel.

I don't think the controler is bad since it is more likey that you have a short on the "heat wire".

Was it running and this just started or are you just wireing it up now?

I would start by disconnecting the controler and going directly to the boiler and then based on the wire plan start it up manualy by jumpering it.

What is the wireing plan type?

Some links
Wireing colors
http://www.toad.net/~jsmeenen/wiring.html

Batery replacment
http://www.howtomendit.com/answers.php?id=23741

[mat 60]

thanks for that.
Got the sparky from work to have a look today,the "earth" wire is in fact the CH live switch from the controler.
The wiring center track has been repaired before by the look of it by bypassing some of the burnt out track.
Managed to get the heating and the hot water to fire up ok but the room stat does not shut the boiler off when at temp.
I have ordered a new wiring center so hopefully it will sort it out when wired up correctly.
only question i have is what is the difference between 'y' 's' 'c' plan systems?

[Bill Arden]

only question i have is what is the difference between 'y' 's' 'c' plan systems?

I don't know, but maybe someone else here can explain.