HALSTEAD ACE HIGH PROBLEM

[pikeman68]

Hello, first time on this forum.
I have an Ace High which only fires up intermittently on both water and heating. Sometimes it runs fine all day but more often it only runs the hot water long enough for a quick shower. At the moment its refusing to do both but will probably run fine for a while in the morning.
The flow switch diaphram was changed and the plate heat exchanger was checked and is clean.
After ignoring a demand for hot water or heating for ages it will then attempt to fire up when there isn't a demand for either.
Its been suggested it could be the air pressure switch, blocked venturi pipes, one or both flow switches and everyones favourite, the pcb.
The pin to the primary flow switch doesnt always pop up when theres a demand but when it does it still doesnt always fire up.
Before all this happened the boiler overheated when the wife ran a bath and I could hear bubbling noises at the top of the boiler and water leaked onto the overheat thermostat from somewhere but that hasnt happened again since the plate heat exchanger was cleaned out.
Any ideas would be greatly appreciated because if its serious it may be better to replace it. Thanks for any help / advice you can give me

 

[twgas]

first thing to do is check the pressure is OK, 1 to 1·5 bar.

 

[Agile]

It seems you have several problems.

If the pin on the primary flow switch does not always rise promptly then thats a flow problem in itself. Possibly dirt or dirt in the pump impeller.

If it still does not start when it does then the switch may be faulty. Test is to measure the contact resistance over 10-20 switch operations ( by hand ).

If it turns out to be gas related then we dont give advice on that here.

Tony

 

[MANDATE]

Daughter had similar problem, intermittent starting. Turned out to be poor joint on pcb.
Boiler does start/run for few seconds every 23 hours without manually switching on. This may explain the attempt to fire up without demand.
You may find this useful.
http://www.haywoodsgroup.com/files/Upload/AceAceHigh.pdf

 

[MANDATE]

and this http://www.ultimatehandyman.org/PDF...e-AceHigh-Installation-Manual-41-333-77-78.pd

 

[ChrisR]

it will then attempt to fire up when there isn't a demand for either

Ah. CHeck/change the microswitch on the water flow.

 

[Agile]

I have to say thats unusual on that model, probably because the switch casing is usually upright.

Whilst it might be the problem, a poor connection on an NTC might be creating a false frost stat operation ( if any ). If that were the case removing and replacing the NTC connectors a couple of times would solve it, better still putting some silicone grease o the pins.

Tony

 

[pikeman68]

Thanks to all who replied.
Have decided to work from home today and keep an eye on the boiler.
In the morning the heating will come on but turn off after half an hour if I dont run the hot water. The pump and fan are running fine. It will then come back on after maybe half an hour and keep cycling like that. The pump runs on for a little while before turning off. The hot water is hit and miss and will run for 2 to 10 minutes. The system was dirty but now has a fernox magnetic filter fitted so wondering if its blocked and thermistor reading that the water in the boiler pipes is hot so just the pump runs until that water has moved on from the boiler. Although if thats the case it should fire up quicker. Is there a diaphram operating the pin in the primary flow micro switch as there seems to be some firring around the retaining clip so maybe that needs replacing. Since the diaphram was changed the retianing clip on the DHW switch is corroding but the pin moves freely.Does the water housing group set filter the fresh water or the central heating water? could both thermistors have started to fail? Sorry its a long winded post but I'm typing as things come to me and just got back from Tokyo after arriving there 2 days before the earthquake.