1 year update DIY heat pump water heater.

[@paladain55]

Man I'm extremely impressed by your ingenuity. This is fantastic.

[@twosuns20]

Thank you for the update.

[@mikecarlson6416]

cool, I think this is absolutely necessary . Higher efficiency is preferred

[@a1234-e1w]

Why did you leave the indoor unit motor? A NE555 pulse generator module can simulate it's feedback to the control board.

[@TomislavKoren]

This is the answer I'm trying to find out. How to get rid of the motor stopping to waste energy.

[@hklfreak5363]

you could use the indoor unit as a subcooler for the refrigerant, so you would be able to heat downstairs for free

[@DaleKlein]

What would you estimate it achieves for COP at lower winter outside air temperatures? Does defrost mode work still on the outdoor unit? Any thoughts on putting the copper coil into an open unpressurized hot water storage tank like a solar drainback system?

[@ne7s29]

Defrost works like it's supposed to but faster since it's in hot water. Cop at low temp I assum is equivalent to the original engineering numbers which is 290% at 5f outside temp running full speed. U can do this is a non pressured water tank sure.

[@mcculloughmike]

It would be sweet if someone could develop an Arduino or raspberry pi to communicate with the outdoor condenser to turn it on and off instead of having to Frankenstein the original indoor board and leave the motor connected.

[@TarasGlek]

what's the max temperate you can reach in the tank, is it 140F or can you go higher? Thinking about doing a similar mod for radiant floor buffer tank.

[@ne7s29]

Tried 130f

[@robertgrann4874]

How do you manage legionnaires? I understand you run at 120F if I recall from a year ago, this is approx 50C which is far from safe in terms of bacteria growth. I'll start play with something like this but was planning to pass the condenser part through a plate exchanger and then using a pump to run one of three heating circuits in tank that already have solar circuits. My concern is efficiency drops, I really like your direct heat solution !

[@robertgrann4874]

As it's impossible to get hold of split systems here in EU atm I'll start as soon as I can exchange our old pump that'll use for domestic hot water. I literally hate all the current solutions as they are way oversized for just domestic water, and the other DHW solutions are built-in/on tank which is inefficient and too costly when shit hits. Arduino/Pi will be the solution to control instead of hacking the head, will be happy to share!

[@dorsetengineering]

Watch heat geeks video on legionella protection. It’s basically a non-issue for domestic users. All a2w users I know have their legionella cycle disabled