Posted by: @derek-m

@kev-m 

When you had your MMSP installed, did they not test and prove that it was functioning correctly before they dashed off into the sunset?

I saw it working up to a point but they obviously didn't check/show me everything.  I got the impression it was the first time they've done it.  They've already been here three times and will need to come again.  I'm very confident they'll be back because I haven't paid them anything for it yet! 

Posted by: @kev-m

Posted by: @derek-m

@kev-m 

When you had your MMSP installed, did they not test and prove that it was functioning correctly before they dashed off into the sunset?

I saw it working up to a point but they obviously didn't check/show me everything.  I got the impression it was the first time they've done it.  They've already been here three times and will need to come again.  I'm very confident they'll be back because I haven't paid them anything for it yet! 

To be quite honest, companies should not be offering a service if they do not know what they are doing. It is not as though it is a particularly complex system. When I commissioned power stations and the like, I don't think my clients would have been particularly impressed if they were not getting all the instrumentation and control system showing the correct information.

Before they leave again, I suggest that you get them to prove that the actual indications are within the specified accuracy.

Posted by: @batalto

@kev-m maybe you want to set your thermostats to 22°. That way you won't suddenly wake up sweating and you'll be able to see what conditions your heating is working in. I was thinking of doing what you're doing, but our heating barely comes on at the moment in the day as the room is 21 or above. No don't really want to set it up 30 and swealter

I was going to do that but it's so easy on my system to move the curve up and down I thought I'd try using that if it gets too hot.  I've also turned the TRVs in the bedroom down a bit.  If I let the thermostats turn it off I'll be back to the falling flow temps and spiky power consumption.

Having said that, the house is 20 deg and rising already so who knows how high it will get. 😆 

Posted by: @derek-m

Posted by: @kev-m

Posted by: @derek-m

@kev-m 

When you had your MMSP installed, did they not test and prove that it was functioning correctly before they dashed off into the sunset?

I saw it working up to a point but they obviously didn't check/show me everything.  I got the impression it was the first time they've done it.  They've already been here three times and will need to come again.  I'm very confident they'll be back because I haven't paid them anything for it yet! 

To be quite honest, companies should not be offering a service if they do not know what they are doing. It is not as though it is a particularly complex system. When I commissioned power stations and the like, I don't think my clients would have been particularly impressed if they were not getting all the instrumentation and control system showing the correct information.

Before they leave again, I suggest that you get them to prove that the actual indications are within the specified accuracy.

Thanks Derek,  I agree.  Having said that, I get the feeling I forced them into it; they were never very willing. I have a growing list of questions to ask them when they come back.  

Been playing with my compensation curve. Scary! Now set as below. Comments?

@morgan 45 at -3, 20 at 20?

Posted by: @batalto

@morgan 45 at -3, 20 at 20?

@batalto

I think what’s what I was told and as per the video linked above?

Is this correct.  Looking at the curve from the main display I see this.  Where did -30c come from?

Revised as per the video.

MCSCERTIFIED.COM "https://mcscertified.com/wp-content/uploads/2020/07/Heat-Pump-Guide.pdf"

All,

I came across this while browsing for information on heat pump design (as you do).  It might be of some interest here and you would think MCS resistered installers would follow it.

Posted by: @kev-m

MCSCERTIFIED.COM "https://mcscertified.com/wp-content/uploads/2020/07/Heat-Pump-Guide.pdf"

All,

I came across this while browsing for information on heat pump design (as you do).  It might be of some interest here and you would think MCS resistered installers would follow it.

Hi Kev,

Thank you for providing the link, I haven't read the whole of the document, but it does make interesting reading.

I note from their estimation of probable SCoP values, that they do not envisage highly efficient systems.

What may be of concern to some of the members, after today's changes to operating parameters, is the possibility of cycling that could occur under mild weather conditions.

For those of you with the time and inclination to do so, you could leave the present settings as they are, and monitor your ASHP for cycling (starting and stopping more than 6 times in a 1 hour period). If cycling should occur then increase the minimum flow temperature setting from 20C to either 25C or back to the origin 30C.

For those of you who don't have the time or inclination to monitor their system, they may find it prudent to change the setting back to its original and see how their system operates from the point of view of temperature control.

I am surprised that the manufacturers did not just incorporate a 10 minute timing function, that would prevent the compressor from restarting when operating at low loads during mild weather conditions. Doing so would not have a marked effect on a home heating system.

An alternative method would be incorporating two compressors within the ASHP, a smaller on for heating and hot water during mild weather and a larger one for Winter use. It may even be possible to run them both together to provide additional capacity during particularly cold spells.

Funny you should say that, mine has settled down to a 3-4 times an hour cycle. I'll post some graphs on my other thread tomorrow.