Boulter Camray 5 repeated stop/start cycle

[Country Bumpkin]

My Boulter Camray 5 was recently serviced by an engineer but has not been right since! This was about 10 days ago.
From an initial start up it runs for about 20 minutes then stops. After 5 minutes or so it restarts, runs for about 5 minutes, stops for 5 minutes, runs for 5 minutes etc. etc. until the thermostat for the water or room tell it to stop. It then stays off until the temperature in either the water tank or room drop enough to fire it up again.
The engineer came back and diagnosed the timer so a new Honeywell progrmmer/timer has been fitted but it's still doing the same thing.
Any ideas please? I will get him back again but would like some idea of what might be wrong rather than changing everything one bit at a time.

 

[oilhead]

Is this a combi or heat only boiler? Either way I can't see it being a timer/programmer problem, but more a control/DHW thermostat OR a circulation problem within the system.

 

[Hairymelon]

Is your home warm. ? Maybe he did a good job and possibly lowered the boiler stat

 

[Country Bumpkin]

Errr - forgive my ignorance but I'm not sure what type of boiler it is! I tried looking it up but am still not clear.
So, I don't think it's a combi boiler as it doesn't provide instant heat. The system heats both the house and the water and there is a hot water tank. If I've understood correctly there is a switch to swap the flow between hot water and the heating. Hopefully that helps?!

A different engineer has just been out and thinks it's a plumbing problem. It was originally a gravity fed system but has been updated with a pump. Apparently the cold water feed should have been plumbed in to about 6" of the pump rather than the couple of feet or so away that it is. In addition, the air bleed valve was closed and the pump turned up to 3. His theory was that air has accumulated in the system which meant that less heat was being extracted so the boiler was getting up to temperature and switching off. Once it cooled down it fired back up etc. He has bled the system, left the valve open and turned the pump down to 1. Hopefully that's it ....

My slight reservation is that the system was changed about 24 years ago when we moved in and has been fine since then.
About 5 or 6 years ago the same same chap who upgraded to the new system cleaned and bled the radiator system ..... perhaps he tweaked the pump and valve .... ? Still seems a while for it run ok though ....

We have the heating and water on for a period in the morning, at lunchtime and again in the evening. He recommended leaving them on at a lower temperature constantly so the boiler doesn't have to work so hard. Seems to make sense ..... I think!

Any thoughts on whether my problem is solved and/or how best to run the system would be much appreciated.