First thing this nmorning my neighbour came round to say there was lots of hot water comingg from the overflow pipe of our house. I can only assume this is the CH/HW system that has malfunctioned. We have an open-vented system witha Vaillant EcoMax Pro 18E.
The water header tank for the CH is not hot. Any suggestions?
Is your CH header tank higher than your header tank for your HW cylinder? If so, you might have a leak in your coil inside the tank.
Tim
VetTec expressed precisely :
You likely have two header tanks, one for the CH and a second for the HW. It sounds like the ball c*ck is passing for one of the two.
Another possibility is that it's open vented HW tank but with a sealed CH system in which case likely culprit is failed expansion vessel. We don't know if it's continuous flow or just a dribble when the system' swarming up.
Basically though, the OP needs to get into the loft and have a look!!
Tim
Sorry for delay in replying but our News Server is down - hence Google Groups.
I have since screwed the bypass valve down much tighter and that seems to have worked. It may be a case of the TRVs all shutting at the same time as the weather is a bit warmer outside? We dont have a thermostat inside the house.
The CH header tank is one floor above the HW cylinder.
You're not making much sense. This should have no effect on any overflows. It may cause your system to "pump over" more if the TRVs shut down.
Some questions that need answering:
Where is the overflowing water coming from? Which header tank?
Is a ball valve running in your loft? Which tank is the ball valve running in?
Is the tank with the running valve the same one as the one overflowing?
Not easy to make an informed diagnosis with so little information.
Tim
But that's not what I asked. Is your CH header tank higher than your HW cylinder header tank, not the cylinder(or is it one of those odd ones with the header tank built into the top of it)?
If the system pressure of your CH system is higher than the pressure in the HW cylinder, a leak in the coil will cause the CH header tank to "top up" your HW cylinder and cause hot water to flow back up to your HW header tank and then out the overflow.
Tim
The CH and HW header tanks are on the same floor with their bases at the same level. The HW header tank however about 20" deep and the CH tank is about 10" deep so the head on the HW is slightly higher. When I get back there tonight I will fire up the system and check the temperature of the HW header tank.
If there is a leak in the coil the higher head on the HW will shove water into the coil, up to the CH header tank and out the overflow as the two tank levels try to equalise. This would heat the CH header tank though which you say was not hot... If it was a bit of dry crisp morning even luke warm water would steam outside and look "hot". A leak such as this would not stop until the HW tank supply is shut off and the tank levels equalise.
Need to establish which warning pipe attached to which tank was/is flowing.
...and?
Tim
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