Sols Posted July 30 Share Posted July 30 Hi - We installed a heat pump to replace a gas boiler about 5 weeks ago. Since then every time I have an issue where when I turn on my shower the water will come out cold/lukewarm for about 30 seconds, then the water will stutter and the shower will screech as it juggles the hot water until it is then sufficiently hot. It's as if once the hot water hits the shower unit all hell breaks loose until its at the correct output. Separately a new issue in the last week since adjusting the flow rate (as we could hear swooshing in some rads which might not be related to this issue at all) I now randomly have no water coming through the shower at all. If I power it off for a few mins and try again it will then work. The plumber has checked for any air pockets, has checked the filter in the shower unit and also adjusted the flow. We have the 8.5Kw heatpump 180L cylinder set at 48 degrees. I have a Mira Event XS Thermostatic power shower. Any suggestions on what to check are welcome. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted July 31 Share Posted July 31 Was your old boiler a combi or did it feed the cylinder? So essentially what has changed? Link to comment Share on other sites More sharing options...
John Carroll Posted July 31 Share Posted July 31 (edited) 8 hours ago, Sols said: Hi - We installed a heat pump to replace a gas boiler about 5 weeks ago. Since then every time I have an issue where when I turn on my shower the water will come out cold/lukewarm for about 30 seconds, then the water will stutter and the shower will screech as it juggles the hot water until it is then sufficiently hot. It's as if once the hot water hits the shower unit all hell breaks loose until its at the correct output. Separately a new issue in the last week since adjusting the flow rate (as we could hear swooshing in some rads which might not be related to this issue at all) I now randomly have no water coming through the shower at all. If I power it off for a few mins and try again it will then work. The plumber has checked for any air pockets, has checked the filter in the shower unit and also adjusted the flow. We have the 8.5Kw heatpump 180L cylinder set at 48 degrees. I have a Mira Event XS Thermostatic power shower. Any suggestions on what to check are welcome. You now have the HW at 48C, what cylinder temp were you maintaining with the gas boiler?, the TMV is doing well to maintain a showering temp of say 40C even though it shouldn't be noisy, do Mira specify a minimum differential temperature for the Event XS?. Some general info, below. Edited July 31 by John Carroll Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 8 hours ago, Sols said: Thermostatic power shower That's the bit that may may need sorting. Do you still have the pump fitted? Is your cylinder an unvented cylinder? A quick look on the Screwfix blurb for that shower, the first thing it says is "Suitable for Low Pressure Water Systems Only", the Q&A section states "The Event XS is a power shower so it requires a cold and hot feed from a gravity supply" if you now have an unvented cylinder you do not have a low pressure system any more. That will be your issue. Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 8 hours ago, Sols said: Separately a new issue in the last week since adjusting the flow rate (as we could hear swooshing in some rads which might not be related to this issue at all) Adjusted the flow rate on what? Link to comment Share on other sites More sharing options...
PhilT Posted July 31 Share Posted July 31 check that all the gate valves (usually circular red wheel handles) are fully open, both around the domestic hot water tank and and loft tank, and if you don't have a loft tank then the Event XS will not work. Link to comment Share on other sites More sharing options...
Sols Posted July 31 Author Share Posted July 31 6 hours ago, MikeSharp01 said: Was your old boiler a combi or did it feed the cylinder? So essentially what has changed? It was a combi boiler so heated the rads and hot water cylinder 4 hours ago, John Carroll said: You now have the HW at 48C, what cylinder temp were you maintaining with the gas boiler?, the TMV is doing well to maintain a showering temp of say 40C even though it shouldn't be noisy, do Mira specify a minimum differential temperature for the Event XS?. The gas boiler was maintained at a medium to high heat setting. I couldn't be more precise but during the cold spell the rads would have been piping hot along with the cylinder and the shower didn't have the same issues at that time. 4 hours ago, JohnMo said: That's the bit that may may need sorting. Do you still have the pump fitted? Is your cylinder an unvented cylinder? A quick look on the Screwfix blurb for that shower, the first thing it says is "Suitable for Low Pressure Water Systems Only", the Q&A section states "The Event XS is a power shower so it requires a cold and hot feed from a gravity supply" if you now have an unvented cylinder you do not have a low pressure system any more. That will be your issue. Yes it's an unvented cylinder image below. What would be the recommendation? A new shower unit as a result? Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 42 minutes ago, Sols said: 7 hours ago, MikeSharp01 said: Was your old boiler a combi or did it feed the cylinder? So essentially what has changed? It was a combi boiler so heated the rads and hot water cylinder That is NOT a combi. That is a system or heat only boiler. A combi boiler has no cylinder. 44 minutes ago, Sols said: Yes it's an unvented cylinder image below. What would be the recommendation? A new shower unit as a result? Your current shower unit is no longer suitable, so will need to be replaced. Good news is you no longer need a power shower, so a mixer will do . Link to comment Share on other sites More sharing options...
John Carroll Posted July 31 Share Posted July 31 (edited) I have seen pumped electric showers fed fom the mains with a reducing valve, it invalidates any warranty but probably not an issue for you, you could install reducing valves on the hot and cold supplies to the shower set to 1.0bar which I think is the maximum allowable inlet head. Edited July 31 by John Carroll Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 15 minutes ago, John Carroll said: I have seen pumped electric showers fed fom the mains with a reducing valve, it invalidates any warranty but probably not an issue for you, you could install reducing valves on the hot and cold supplies to the shower set to 1.0bar which I think is the maximum allowable inlet head. That's a bit bonkers, take mains pressure water, drop the pressure, use a pump to make it high pressure again. 1 Link to comment Share on other sites More sharing options...
John Carroll Posted July 31 Share Posted July 31 12 minutes ago, JohnMo said: That's a bit bonkers, take mains pressure water, drop the pressure, use a pump to make it high pressure again. Not ideal of course, or if the remaining users can put up with 1.0bar H&C maybe just reduce the UV cylinder PRV to 1.0/1.5bar, wonder what pressure its actually running at with 15/20 LPM draw off even if set to 3.0bar. Link to comment Share on other sites More sharing options...
Sols Posted July 31 Author Share Posted July 31 8 hours ago, JohnMo said: That is NOT a combi. That is a system or heat only boiler. A combi boiler has no cylinder. Your current shower unit is no longer suitable, so will need to be replaced. Good news is you no longer need a power shower, so a mixer will do . Yes correct - apologies on terminology I've just moved in recently and started the changes in the house. I suspect the shower has been in there since day 1 so close to 20 years ago. Will look at replacing the shower for something that is suitable for a vented system, will hopefully report good news in due course. Thanks for all the help so far! Link to comment Share on other sites More sharing options...
JohnMo Posted July 31 Share Posted July 31 12 minutes ago, Sols said: replacing the shower for something that is suitable for a vented system, Slight typo - vented should read unvented, for anyone else reading 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now