Posted by: @derek-m

@editor Hi Mars,

My earlier comment about being ignored is in relation to quite a number of posts to which I have responded recently and there has been no response. I therefore wonder if I am wasting my time when there are still members who continue to switch the heat pumps on and off.

Regarding people not replying to responses is not uncommon on forums.

It's not a waste of time though, because this content is available to everyone, and there will be people with questions that stumble across your answers via a google search which will help them, and they may never acknowledge it. We get a lot of traffic from google where I can see people consuming content without ever registering an account. 

@editor Hi Mars,

I appreciate what you are saying, but for the forum to be most productive it is necessary for the forum members to at least give feedback as to what works and what does not work, otherwise how will we know that the information provided was relevant, of use and that their problem has been resolved.

@editor Weather compensation has no complex logic. It is just a straight line graph that is used by the machine to determine the flow temperature. High ambient temp = low flow temp and low ambient = low flow temp.

I can show you why your COP is low.

Buffer tank - reduces performance by 30-40%

Any TRV's can reduce the performance of the system by another 30%.

Zoning under floor heating can reduce it by another 40%

To control temperature output of an emitter, you have to reduce the temperature, that means you have to start high, and cut it at each stage with each level of control. Fine with a boiler but not a heat pump.

Your heat pump does not stand a chance, it's leg is tied to an anchor and it's arms are tied together between it's legs, and you are expecting it to beat Usain Bolt in the 100 meters. Not a chance.

Remove your buffer tank, remove all the thermostats and actuators on your under floor, remove all TRV's on all the radiators except your bedroom and control the house temperature by altering the weather compensation curve. It will be a little trial and error but when you get it right, you will not have to touch it again.

If you do this, I believe you will be able to remove you oil boiler it will not be necessary. If you do not want to remove your buffer yet (which you do not need) just remove the actuators on the under floor and TRV's, set the flow temp to about 26, leave it for a few days, your house should be toasty and your COP will be drastically improved. (do you have pumps and mixing valves on your manifold?)

Why worry about the running costs, you are getting paid for it on the RHI the more the heat pump works, the more you get paid. You need to improve your performance to reduce you running costs. Currently at a COP of 3, at this ambient temperature, I would be verry embarrassed if I had installed this, it is terrible.

@editor Mars, unfortunatly you are paying for the inadiqicyes of your friend, Ian Rippon and his MCS system.

It is just not fit for purpose.

Posted by: @heacol

@editor Mars, unfortunatly you are paying for the inadiqicyes of your friend, Ian Rippon and his MCS system.

It is just not fit for purpose.

Brendon,

Having been a Consultant Engineer for many years, I found it much more productive to suggest 'improvements' to the client or suppliers design, rather than tell them that it is a load of rubbish and that they should all be fired on the spot.

One thing that needs to be considered is that the people on the forum have spent a great deal of money on an ASHP system and have trusted the installer to provide a fully functional working system. To now be told they have made a big mistake is usually not well received. The best that we can hope to do is identify the weaknesses in their present system and suggest ways in which their system can be optimised without involving major modifications and subsequent costs.

What I find particularly annoying and frustrating, is that after spending an hour or more downloading and reading the information relating to a particular persons system, and then suggesting simple tests or clarification of how they operate their system, one does not get a reply. Some time later the same person may once again be complaining about their system on the forum.

Clients were happy to pay £50 per hour for my knowledge and experience, so maybe rather than providing it for free we should start charging. Perhaps people would then listen to common sense and experience.

I fully agree that MCS would appear to be not fit for purpose.

@derek-m

I agree, unfortunately this industry is self-destructing and nobody seems to care, it is very frustrating. I hope, someone will read my contributions and take note. I repair a lot of systems an charge £70.00 pe hour for the consultation.

Here is a picture of what we removed from the last installation, all this

copper, 5 pumps and 7 motorised valves. There were also 2 X 200 litter cylinders (not in the picture). The system now heats the house perfectly, we did not change or upgrade a single radiator. So near but So far.

Posted by: @derek-m

@editor Hi Mars,

I appreciate what you are saying, but for the forum to be most productive it is necessary for the forum members to at least give feedback as to what works and what does not work, otherwise how will we know that the information provided was relevant, of use and that their problem has been resolved.

I take your point Derek. Some users just aren't courteous unfortunately to say thank you or acknowledge the time you've spent replying to them.

Posted by: @heacol

@editor Mars, unfortunatly you are paying for the inadiqicyes of your friend, Ian Rippon and his MCS system.

It is just not fit for purpose.

I understand that the MCS may have its faults, but I shudder to think what the quality of installs would be without it, and it least MCS gives homeowners some recourse to get botched installations remedied.

@heacol, the practicalities of getting the system running the way you describe would involve a lot of remedial work given that we've inherited a flawed piping network for our central heating, and it's simply not feasible at this time.

In terms of running the heat pump to get RHI payments – when it gets really cold, we can use upwards of 80-90kWh per day. At current tariffs, that makes things very expensive to run, so the oil boiler will do the heavy lifting when temperatures drop to a level when the heat pump loses efficiency – this is a financial no-brainer for us and we'll derive the maximum RHI payments based on our winter and spring ASHP heat generation. 

@editor

Actually Mars, it would make more financial sense to get your system fixed, you would not drive your car with flat tyres. There is not much wrong, any good plumber could fix it in a morning.

Posted by: @editor

Posted by: @heacol

@editor Mars, unfortunatly you are paying for the inadiqicyes of your friend, Ian Rippon and his MCS system.

It is just not fit for purpose.

I understand that the MCS may have its faults, but I shudder to think what the quality of installs would be without it, and it least MCS gives homeowners some recourse to get botched installations remedied.

Actually there has been little change from prior to MCS being launced appart from an indcrease in the price of installations by 2000-3000 pounds, there has always been protection through Trading Standards, now same people with a different name, (RECC) and a higher price tag.

I am not against standards if they produce high quality installations, I am against standards that allow installers to install systems like yours that are not fit for purpose. Your system is costing you a lot of money and making you uncomfortable because of poor design.

Posted by: @derek-m

Posted by: @editor

Posted by: @heacol

@editor Low flow temperatures = low bills. It realy is that simple.

Fabric first to achieve low flow temperatures I guess. Our insulation is good to very good, but we still leak some heat. Getting better though.

Hi Mars,

I am beginning to wonder if anyone bothers to read the information that I provide. Having been a Control Systems Engineer for over 50 years and worked on and designed systems for power stations and oil and gas processing plants, thermostats would only be used on the systems of low importance. The problem with using thermostats in home heating systems is that they normally have a deadband of 1C, which means that to maintain a comfortable temperature within the home, they are normally set higher than would need to be if continuous process control was used instead of a thermostat.

To confirm the point that Brendon and I have been repeatedly making, for maximum efficiency an ASHP needs to be operating at the lowest water flow temperature that is consistent with maintaining the desired indoor air temperature. At the moment, with an outside air temperature of 12C, our radiators are cold to the touch, with our heating system in full operation maintaining an indoor temperature of 21C. When the outside air temperature falls to 6C, the radiators are only just warm to the touch.

If you take the trouble to look at the spreadsheets and results that I posted several weeks ago, you will see that ASHP efficiency is most affected by outside air temperature, indoor set temperature, heat loss (level of imsulation) and size of heat emitters.

Even the most expensive, supposedly intelligent heating controls, are not often used correctly with heating system that employ an ASHP.

 

Thanks for your input on this topic guys, they are I'm sure, appreciated by many people who are trying to get to grips with their ASHP.

I don't think it's a situation of people not being bothered to read the information that you provide, more likely it's not easy to find. As the forum topics grow we end up with pages of replies, sometimes unintentionally being derailed and discussing other, more specific issues.

Derek, could you possibly add a link to the post you are referring to so it's easier to find for future reference please?