I have a Baxi combi boiler that keeps running the shower hot and cold. I have replaced the cartridge in the shower - twice - but the problem persists. No other taps are affected and our second shower works fine and all are fed by the same combi. When this shower is used I can see the boiler lights showing it heat the water, then it stops heating, then it comes back on and repeats the cycle over and over. Any ideas please !!!
Combi boiler going hot and cold
- Thread starter Jimefc
- Start date
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More than likely the hydraulic Venturi. Could be a partially blocked plate heat exchanger too.
Baxi make a lot of different combi boilers
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This boiler uses a Hall sensor to detect flow so I’m leaning towards a blocked plate if pulsing hot and cold.
The shower also needs to pass enough hot water to keep the boiler lit.
Try running a hot tap slightly when running the shower. This should keep the boiler firing if it’s not the plate.
The shower also needs to pass enough hot water to keep the boiler lit.
Try running a hot tap slightly when running the shower. This should keep the boiler firing if it’s not the plate.
Just tried running the shower with a hot tap as well and it kept its temperature - thanks for the suggestion. Looks like I now need to replace the plate heat exchanger so that's great news as its a solution. One again many thanks Jeff
You are welcome mate.
Brick acid bath could unblock your current plate and worth a shot. Be careful tho obvs.
Also don’t fit flow restrictions to shower outlet. Make sure hose and head is in good condition.
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