No hot from taps

Drained the system for winter and re-filled recently. The cascade boiler is full and pressurised but any small amount of water from the hot taps just dribbled and stops, pump does not kick in. If i run a cold tap on full and open the hot it seems to work when I turn the cold off but after shutting the hot again and trying it, nothing. Any suggestions. The van has hardly been used, should not be wear and tear.

Hi Davy
Welcome to the forum from Bridlington , used to live on the next Island west of you ,Bute.
One of the forum members who is familiar with your system will help you soon.
Boaby

Sounds like it could be the micro switch contacts.....

redturner37 wrote:Sounds like it could be the micro switch contacts.....

Autosleeper use pressure controlled water pumps and do not have microswitches on the taps.

For the pump to operate there needs to be a reduction in pressure in either the cold or hot water circuit. As the pump only operates when the pressure is reduced (tap opened) in the cold circuit there must be a blockage in the hot water circuit somewhere after it splits from the cold (just before the water heater) or in the hot water tap itself............

Just realised older van with carver heater, there is a vent screw at the top on the outside. You probably opened it to drain the boiler - have you closed it again?

Oooooops, my Convoy had micro switches, my AS doesnt. Should put brain in gear before cranking fingers up......My shower has switched taps but not wired up.....

Peter Brown wrote:

redturner37 wrote:Sounds like it could be the micro switch contacts.....

Autosleeper use pressure controlled water pumps and do not have microswitches on the taps.

For the pump to operate there needs to be a reduction in pressure in either the cold or hot water circuit.  As the pump only operates when the pressure is reduced (tap opened) in the cold circuit there must be a blockage in the hot water circuit somewhere after it splits from the cold (just before the water heater) or in the hot water tap itself............

Just realised older van with carver heater, there is a vent screw at the top on the outside.  You probably opened it to drain the boiler - have you closed it again?

Yes the vent screw is closed, any suggestions ? I dont know why first time its been drained, it wont work. The van has done 6000miles only

Only the suggestions I've already made about a blockage in the hot water system. Mileage is irrelevant.

This problem could be of interest to quite a lot of Topaz owners.
Could you post details of the solution when this is resolved please.
Keith

Hi there,

Have you given it enough time?

It can take a long time to fill the reservoir; especially if you have left a drain plug out or a relief valve open!

Normally, "Seek and ye shall find." applies to this situation and it's usually "Operator Error" rather than sometime significantly wrong.

(I was once at the point of buying a new pump before SWMBO pointed out that there was a lot of water pouring out of the side of the van; where I had left the heater's drain plug out!!)   

Hope this helps. 

Best regards,