Advice on a Daikin Altherma 3 by Octopus

Wizard2

FreeBear said:

Wizard2 said:

FreeBear said:

Wizard2 said: I'm in East Anglia and the radiators have 10mm copper pipes.

Would it be hard to go back to gas if we really hated it (the gas boiler is our last gas appliance)?

Is it just 10mm going to the radiators from larger pipes, or is the whole system plumbed in 10mm ?

If you find an ASHP unsuitable, as long as you still have a gas supply, it wouldn't be too difficult to reinstate a boiler. If you kept the ASHP as part of a hybrid system, you'd be able to run the HP at a high COP on the warmer days, and just use gas for a boost when cold outside. To convert to a hybrid system wouldn't be very cheap though. The money would be better spent on replumbing the existing system (bigger pipes, larger radiators) and improving insulation levels.

I've had a look at the current setup, and after doing some research, I think I mostly understand what all the pipes I can see do.

There's 22mm from the boiler to the hot water cylinder, and 22mm for the radiators, which goes into the floor. I'm not sure at which point it becomes 10mm piping. There's also a 15mm pipe connected before the pump in the airing cupboard, but I'm not sure what that's for.

The new water cylinder would be going in the garage, where the boiler currently is, since the airing cupboard would be too small for the new equipment. Octopus would use the boiler flow and return pipes with a new cylinder, and then hot and cold water pipes from the kitchen, which are 15mm. Does the size of the hot and cold pipes matter too much?

A table about a third of the way down on this page might be of interest - https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/ - A 10mm pipe will only be able to carry a little less than half that of a 15mm pipe. How much heat you need to pump through that pipe depends on the radiator size.

To my mind, 15mm should be fine for domestic hot water, especially if you have an unvented tank. Some say you need to increase the size to 22mm. I don't think it really matters as the taps will limit how much water will flow, especially if you have mixer taps with 8mm tails.

Thanks for that, I'd come across that page before but I hadn't looked into it properly. Does the table work for both the whole house and for individual rooms? For example, considering 22mm pipes for the whole house with Octopus' heat loss calculation of just over 6kW, and then 10mm with up to 1kW as the maximum heat output for a single radiator?

If so, and I've interpreted the table correctly, I think the pipes should be okay! But, I feel like I should look under the floorboards to see when the pipes become 10mm...

That sounds good about the domestic hot water, I thought the same about the taps restricting flow.

FreeBear

Wizard2 said:

FreeBear said:

Wizard2 said:

FreeBear said:

Wizard2 said: I'm in East Anglia and the radiators have 10mm copper pipes.

Would it be hard to go back to gas if we really hated it (the gas boiler is our last gas appliance)?

Is it just 10mm going to the radiators from larger pipes, or is the whole system plumbed in 10mm ?

If you find an ASHP unsuitable, as long as you still have a gas supply, it wouldn't be too difficult to reinstate a boiler. If you kept the ASHP as part of a hybrid system, you'd be able to run the HP at a high COP on the warmer days, and just use gas for a boost when cold outside. To convert to a hybrid system wouldn't be very cheap though. The money would be better spent on replumbing the existing system (bigger pipes, larger radiators) and improving insulation levels.

I've had a look at the current setup, and after doing some research, I think I mostly understand what all the pipes I can see do.

There's 22mm from the boiler to the hot water cylinder, and 22mm for the radiators, which goes into the floor. I'm not sure at which point it becomes 10mm piping. There's also a 15mm pipe connected before the pump in the airing cupboard, but I'm not sure what that's for.

The new water cylinder would be going in the garage, where the boiler currently is, since the airing cupboard would be too small for the new equipment. Octopus would use the boiler flow and return pipes with a new cylinder, and then hot and cold water pipes from the kitchen, which are 15mm. Does the size of the hot and cold pipes matter too much?

A table about a third of the way down on this page might be of interest - https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/ - A 10mm pipe will only be able to carry a little less than half that of a 15mm pipe. How much heat you need to pump through that pipe depends on the radiator size.

To my mind, 15mm should be fine for domestic hot water, especially if you have an unvented tank. Some say you need to increase the size to 22mm. I don't think it really matters as the taps will limit how much water will flow, especially if you have mixer taps with 8mm tails.

Thanks for that, I'd come across that page before but I hadn't looked into it properly. Does the table work for both the whole house and for individual rooms? For example, considering 22mm pipes for the whole house with Octopus' heat loss calculation of just over 6kW, and then 10mm with up to 1kW as the maximum heat output for a single radiator?

If so, and I've interpreted the table correctly, I think the pipes should be okay! But, I feel like I should look under the floorboards to see when the pipes become 10mm...

22mm should be good for 6kW at 0.9mps/DT5. If you find it isn't, increase the pump speed or the DT.

I replumbed my heating system last year with the goal of making it heat pump ready, Used 22mm for the main feed & return with 15mm tails to the radiators. Having decided on where a cylinder would be located, the final 4m will be done in 28mm and pick up on the 22mm pipes just where three radiators branch off - That would reduce the amount of heat being carried by the 22mm pipes by about a third. Still collecting data (waiting for sub-zero weather), but it looks like I only need 3-4kW to keep this place warm and 6-8kW to raise the temperature at a rate of 1°C per hour.

If/when you lift floorboards, make a note of the length of the tails - You may find it is a relatively trivial task to swap the 10mm out for 15mm.

Wizard2

Nick_Dr1 said:

Wizard2 said:

Adrian_Dorr said:

 Whey mean is that you can’t can’t change the design temperature. Using a weather curve setting the system will constantly change the temperature and only go to 50C when the outside temperature is at the design temperature, I.e. the minimum outside temperature that you get at your location (e.g. -2C in the south). 

You can change that in the settings later when you find that your house gets too warm. 

When you say it will only go to 50°C when the outside temperature is at the minimum, does that mean by default it'd typically be higher than 50°C, dropping to 50°C at the minimum?

No, it means that the maximum temperature it will heat the heating water to is 50deg. It does this when it is really cold outside to get the maximum heat into the house. Under these conditions the house is losing maximum heat through the walls etc.
When its not so cold outside, the house needs less continuous heat input as less is escaping. If you heated the water to 50 deg then the house would get too hot and the heat pump would turn off. Then it would turn on again later when the house has cooled etc . This is cycling. What the system does is set a lower temperature for the water if its warmer outside and so it heats the house slower, ideally just balancing the heat in against the heat out. Pump runs for longer (all day) but at a lower power input, sand this is efficient. Starting and stopping is inefficient.

Ah I see, thank you for that explanation! I had it the wrong way around in my head.

Wizard2

FreeBear said:

Wizard2 said:

FreeBear said:

Wizard2 said:

FreeBear said:

Wizard2 said: I'm in East Anglia and the radiators have 10mm copper pipes.

Would it be hard to go back to gas if we really hated it (the gas boiler is our last gas appliance)?

Is it just 10mm going to the radiators from larger pipes, or is the whole system plumbed in 10mm ?

If you find an ASHP unsuitable, as long as you still have a gas supply, it wouldn't be too difficult to reinstate a boiler. If you kept the ASHP as part of a hybrid system, you'd be able to run the HP at a high COP on the warmer days, and just use gas for a boost when cold outside. To convert to a hybrid system wouldn't be very cheap though. The money would be better spent on replumbing the existing system (bigger pipes, larger radiators) and improving insulation levels.

I've had a look at the current setup, and after doing some research, I think I mostly understand what all the pipes I can see do.

There's 22mm from the boiler to the hot water cylinder, and 22mm for the radiators, which goes into the floor. I'm not sure at which point it becomes 10mm piping. There's also a 15mm pipe connected before the pump in the airing cupboard, but I'm not sure what that's for.

The new water cylinder would be going in the garage, where the boiler currently is, since the airing cupboard would be too small for the new equipment. Octopus would use the boiler flow and return pipes with a new cylinder, and then hot and cold water pipes from the kitchen, which are 15mm. Does the size of the hot and cold pipes matter too much?

A table about a third of the way down on this page might be of interest - https://www.heatgeek.com/does-my-pipework-need-upgrading-for-a-heat-pump-with-cheat-sheet/ - A 10mm pipe will only be able to carry a little less than half that of a 15mm pipe. How much heat you need to pump through that pipe depends on the radiator size.

To my mind, 15mm should be fine for domestic hot water, especially if you have an unvented tank. Some say you need to increase the size to 22mm. I don't think it really matters as the taps will limit how much water will flow, especially if you have mixer taps with 8mm tails.

Thanks for that, I'd come across that page before but I hadn't looked into it properly. Does the table work for both the whole house and for individual rooms? For example, considering 22mm pipes for the whole house with Octopus' heat loss calculation of just over 6kW, and then 10mm with up to 1kW as the maximum heat output for a single radiator?

If so, and I've interpreted the table correctly, I think the pipes should be okay! But, I feel like I should look under the floorboards to see when the pipes become 10mm...

22mm should be good for 6kW at 0.9mps/DT5. If you find it isn't, increase the pump speed or the DT.

I replumbed my heating system last year with the goal of making it heat pump ready, Used 22mm for the main feed & return with 15mm tails to the radiators. Having decided on where a cylinder would be located, the final 4m will be done in 28mm and pick up on the 22mm pipes just where three radiators branch off - That would reduce the amount of heat being carried by the 22mm pipes by about a third. Still collecting data (waiting for sub-zero weather), but it looks like I only need 3-4kW to keep this place warm and 6-8kW to raise the temperature at a rate of 1°C per hour.

If/when you lift floorboards, make a note of the length of the tails - You may find it is a relatively trivial task to swap the 10mm out for 15mm.

Unfortunately, we didn't consider the heating system before redecorating half of the house, so it'd be preferable to not need to upgrade pipes! A couple of rooms don't have new carpet yet, so I don't mind lifting those floorboards in those.

Just out of interest, would you consider Octopus for when you get a heat pump, or would you prefer a different installer (if you've even thought about it yet!)?

Wizard2

One last thing on my mind about a heat pump installation is the mess caused. We've redecorated half the house (we should have really upgraded the heating system first), so we don't want to need to replace carpets that are only a couple of months old, or repaint huge sections of walls. I was told at Octopus that they wouldn't lift floorboards, but noticed one case where someone had floorboards lifted.

There's also the wired thermostat. Has anyone here had one installed in a position where there wasn't a previous wired thermostat?

What experiences have people had on here?

FreeBear

Wizard2 said: Just out of interest, would you consider Octopus for when you get a heat pump, or would you prefer a different installer (if you've even thought about it yet!)?

Based on price alone, I would certainly go for an Octopus install. Most of the pipework is heat pump ready and wouldn't need any big changes if larger radiators are needed. Only problem area would be where pipes would run through the kitchen - Will need to pull base units out to gain access, so will wait until I revamp the kitchen before putting in the last bit of pipework.

Wizard2

FreeBear said:

Wizard2 said: Just out of interest, would you consider Octopus for when you get a heat pump, or would you prefer a different installer (if you've even thought about it yet!)?

Based on price alone, I would certainly go for an Octopus install. Most of the pipework is heat pump ready and wouldn't need any big changes if larger radiators are needed. Only problem area would be where pipes would run through the kitchen - Will need to pull base units out to gain access, so will wait until I revamp the kitchen before putting in the last bit of pipework.

Ah yes, that's what I was thinking too with the price. Heat Geek estimated a price more than £2000 higher, so I'm not convinced it'd be worth spending £375 for a survey.

Exiled_Tyke

Wizard2 said:

One last thing on my mind about a heat pump installation is the mess caused. We've redecorated half the house (we should have really upgraded the heating system first), so we don't want to need to replace carpets that are only a couple of months old, or repaint huge sections of walls. I was told at Octopus that they wouldn't lift floorboards, but noticed one case where someone had floorboards lifted.

There's also the wired thermostat. Has anyone here had one installed in a position where there wasn't a previous wired thermostat?

What experiences have people had on here?

most of my replacement radiators have simply slotted in to the old pipework.  A couple of them are wider so they have extended the pipes from the current ones. It's a bit messy but better than putting more holes in the carpets or walls.   

I previously had a Hive thermostat so not wired. Fortunately the new one for me has been drilled through from the garage so no mess or issues there at all.  I think you'd have to agree with the surveyor where the best location is for wiring and heat measurement.   I presume that the Octopus terms are still the same - if you aren't happy with the proposed scheme you can back out and get the deposit back?