Great explanation Tom. I wish I'd known a little more before we got our ASHP installed late 2022, but it's worked out fine in the end. We have hydraulic separation with a secondary heat exchanger to allow the HP to run optimally, while the existing old central heating system has it's own pump & can run a little different to cope with mixed 22mm, 15mm and 10mm pipework sizes. We also have a couple of longer pipe runs and low output towel warmers needing a bit more flow and higher DT that separation can help with. If designing again from scratch I'd do what I think you are doing which is properly plan for an efficient 'open loop' solution, no separation or buffers and one pump inside the ASHP for everything.
The devil is in the detail. That becomes more obvious the more I learn. Good design is key to an efficient system. Glad you got the issues resolved and that yours is working well.
I'm with you on this one Tom as I'm in the same situation. I've already got a solar & battery system so this is the next logical step for me. Unfortunately my existing radiators have 10mm microbore pipework so this presents a large problem as far as flow rates are concerned & major upheaval issues if these pipes need to be replaced. Because we have an uninsulated concrete ground floor, my ground floor rads are served by 10mm pipes from the 1st floor behind the D&D plasterboard walls in each room. Replacing these pipes would cause major disruption throughout the whole house. As a result I am also considering an Air to Air system as well which would be less intrusive to install, give us a cooling facility for summer coupled with a separate HW heating solution e.g. HP Hot Water cylinder (Mixergy iHP) or a Phase change Hot Water battery (SunAmp). Looking forward to your next vid to see how you progress.
It might not be a massive issue. You really have to work out how they are all connected and then work backwards like I've done. 10mm pipe will carry 1.1kW at optimum speed, so if you had higher speed, you could increase that. It would be worth drawing a diagram if you can.
Me too!. I began my ASHP journey a year ago and did my heat loss analysis then. A year down the line, I've learned a lot and intend revisiting my analysis. I've already got a map of my pipework and know the gauges in most sections. Difficult areas are the boiler flow/return and the microbore to two column radiators in my recently renovated kitchen/diner. I'm really kicking myself that I didn't insist on a 3rd column radiator and replacing the microbore in the walls while I had the opportunity. Rather than having an 'Upstairs' and a 'Downstairs' manifold arrangement, I have a 'North' and 'South' arrangement. The North manifold runs along an upstairs corridor and will be straightforward to replace, if necessary. The South manifold runs under a tiled bathroom floor and in the walls (it's a split-level property), so I won't be changing that. Progress on my journey has been slowed as I'm still trying to get my PV and house battery sorted. I decided last year that this should be my priority while I monitored my heating system closely this heating season. I was ready to press the button on my PV and battery last November but I'm still waiting on the DNO 😒.
@@IanMK13 We may be close if your MK13 is a post code? I'm MK12. I got myself one of those Topdon thermal camera thingy's for my iPhone so I can trace where all the hot pipes are located & where they split off. My wall hung boiler pipes are accessible & are 22mm F & R up to the airing cupboard on our 1st floor landing & off to the rads under the 1st floor T&G chipboard floor. Not done our heat loss calcs yet but it's a 1986 house with filled cavity walls & only 100mm insulation in the loft which is my next job - raise the chipboard floor I put in 35 years ago & add an extra 200mm of insulation (minimum). As I said above I may go Air to Air as it's cheaper & easier to install with less upheaval but, no grants currently available other than 5% VAT if it's still valid. Undecided about this ATM.
@@colingoode3702 MK13 when I created my TH-cam account. Now MK15. 1990 house and I increased the loft insulation last year. Loft only partially boarded, so I didn't bother adding insulation there, on the basis that the loft panels will have a U-value of their own (although maybe not as good as extra insulation). I considered A-A to augment the existing kitchen rads but my wife has sensitive hearing and doesn't want the fan noise. Not sure about DHW at present - low static pressure, low flow rate, 2 existing pumped shower units so I probably want to keep a vented cistern with loft water tanks (In any case, removing the weight from the loft would probably lead to cracks in the rooms beneath 🤣🤣🤣)
Tom, I’m hooked. This series you propose is going to be very important for me and (hopefully) many others. Thank you. (Also very much enjoyed your other videos). In my case I’d be transitioning from oil rather than gas. Potentially one of my issues is most of the peripheral radiator pipe work is 10mm rather than 15mm (although the spine is 28mm I think).
10mm pipe can carry quite a lot at dT 5. It would be worth drawing a diagram like I did. Then you could work out where the pinch points are. In my video, I used the optimum, so there is wiggle room if you move the water a little faster.
Great explanation Tom. I wish I'd known a little more before we got our ASHP installed late 2022, but it's worked out fine in the end. We have hydraulic separation with a secondary heat exchanger to allow the HP to run optimally, while the existing old central heating system has it's own pump & can run a little different to cope with mixed 22mm, 15mm and 10mm pipework sizes. We also have a couple of longer pipe runs and low output towel warmers needing a bit more flow and higher DT that separation can help with. If designing again from scratch I'd do what I think you are doing which is properly plan for an efficient 'open loop' solution, no separation or buffers and one pump inside the ASHP for everything.
The devil is in the detail. That becomes more obvious the more I learn. Good design is key to an efficient system.
Glad you got the issues resolved and that yours is working well.
I'm with you on this one Tom as I'm in the same situation.
I've already got a solar & battery system so this is the next logical step for me.
Unfortunately my existing radiators have 10mm microbore pipework so this presents a large problem as far as flow rates are concerned & major upheaval issues if these pipes need to be replaced. Because we have an uninsulated concrete ground floor, my ground floor rads are served by 10mm pipes from the 1st floor behind the D&D plasterboard walls in each room. Replacing these pipes would cause major disruption throughout the whole house. As a result I am also considering an Air to Air system as well which would be less intrusive to install, give us a cooling facility for summer coupled with a separate HW heating solution e.g. HP Hot Water cylinder (Mixergy iHP) or a Phase change Hot Water battery (SunAmp).
Looking forward to your next vid to see how you progress.
Colin, this is a good reply and very interesting as we seem to be in a similar situation. Your later detail and thoughts are good information!
It might not be a massive issue. You really have to work out how they are all connected and then work backwards like I've done. 10mm pipe will carry 1.1kW at optimum speed, so if you had higher speed, you could increase that. It would be worth drawing a diagram if you can.
Me too!.
I began my ASHP journey a year ago and did my heat loss analysis then. A year down the line, I've learned a lot and intend revisiting my analysis. I've already got a map of my pipework and know the gauges in most sections. Difficult areas are the boiler flow/return and the microbore to two column radiators in my recently renovated kitchen/diner. I'm really kicking myself that I didn't insist on a 3rd column radiator and replacing the microbore in the walls while I had the opportunity. Rather than having an 'Upstairs' and a 'Downstairs' manifold arrangement, I have a 'North' and 'South' arrangement. The North manifold runs along an upstairs corridor and will be straightforward to replace, if necessary. The South manifold runs under a tiled bathroom floor and in the walls (it's a split-level property), so I won't be changing that.
Progress on my journey has been slowed as I'm still trying to get my PV and house battery sorted. I decided last year that this should be my priority while I monitored my heating system closely this heating season. I was ready to press the button on my PV and battery last November but I'm still waiting on the DNO 😒.
@@IanMK13 We may be close if your MK13 is a post code? I'm MK12. I got myself one of those Topdon thermal camera thingy's for my iPhone so I can trace where all the hot pipes are located & where they split off. My wall hung boiler pipes are accessible & are 22mm F & R up to the airing cupboard on our 1st floor landing & off to the rads under the 1st floor T&G chipboard floor. Not done our heat loss calcs yet but it's a 1986 house with filled cavity walls & only 100mm insulation in the loft which is my next job - raise the chipboard floor I put in 35 years ago & add an extra 200mm of insulation (minimum). As I said above I may go Air to Air as it's cheaper & easier to install with less upheaval but, no grants currently available other than 5% VAT if it's still valid. Undecided about this ATM.
@@colingoode3702 MK13 when I created my TH-cam account. Now MK15. 1990 house and I increased the loft insulation last year. Loft only partially boarded, so I didn't bother adding insulation there, on the basis that the loft panels will have a U-value of their own (although maybe not as good as extra insulation). I considered A-A to augment the existing kitchen rads but my wife has sensitive hearing and doesn't want the fan noise.
Not sure about DHW at present - low static pressure, low flow rate, 2 existing pumped shower units so I probably want to keep a vented cistern with loft water tanks (In any case, removing the weight from the loft would probably lead to cracks in the rooms beneath 🤣🤣🤣)
Tom, I’m hooked. This series you propose is going to be very important for me and (hopefully) many others. Thank you. (Also very much enjoyed your other videos). In my case I’d be transitioning from oil rather than gas. Potentially one of my issues is most of the peripheral radiator pipe work is 10mm rather than 15mm (although the spine is 28mm I think).
10mm pipe can carry quite a lot at dT 5. It would be worth drawing a diagram like I did. Then you could work out where the pinch points are. In my video, I used the optimum, so there is wiggle room if you move the water a little faster.