I remember having this problem before...10 years ago. Temperature would go up then down, then up, then down. Its to do with the fact that the water pipes that take water from the engine to the hotwater cylinder are about 6 metres long and they come from the engine to the hotwater cyclinder and then back to the thermostat housing on the engine.
This happened years ago when I replaced the thermostat. At the time I asked the old guy that used to look afte all the mechanicals on Diva and he said, ah you don't have any holes in the rim to act as a bypass. The thermal inertia of all that water in those pipes is what causes the issue.
Well the thermostat we put in on Friday had 4 holes in it. The old one we took out had 6.
So this morning I've taken the thermostat out and drilled 2 more holes in it.
Now the engine takes longer to warm up, but it doesn't get into this cycling business with the thermostat unable to control the running temperature.
So, all good now ?....Let's hope so !
This happened years ago when I replaced the thermostat. At the time I asked the old guy that used to look afte all the mechanicals on Diva and he said, ah you don't have any holes in the rim to act as a bypass. The thermal inertia of all that water in those pipes is what causes the issue.
Well the thermostat we put in on Friday had 4 holes in it. The old one we took out had 6.
So this morning I've taken the thermostat out and drilled 2 more holes in it.
Now the engine takes longer to warm up, but it doesn't get into this cycling business with the thermostat unable to control the running temperature.
So, all good now ?....Let's hope so !