Samsung 8kw R32 Monobloc Air Source Heat Pump

[Ceridunn]

Hi, I have just installed a Samsung 8kw R32 Monobloc Air Source Heat Pump, just to run underfloor heating, I was under the impression I would not need an external pump, but I am getting no flow when selecting heat, can anyone tell me if the ashp I have has an internal pump? Cheers in advance. 

[akjos]

If I remember correctly, Samsungs don't have an internal pump. So you need one pump external to the unit which will run your system. I'm not sure about the latest generations though. You can easily check it by popping the lid and seeing if there's a pump in there by the water heat exchanger.

Flow rate is the most important thing of a heat pump and each needs about 2x-2.5x the capacity in l/min. So in your case (8kw), you need around 16-20l/min flow rate running always when your heat pump is on. In a simple system (no buffer, no LLH etc), you need to make sure all your UFH loops are open and the total flow rate across them matches your required 16-20l/min.

If you have zones that close, you will need either a bypass valve to make sure you have the required flow when zones close, or do hydraulic separation with a LowLossHeader. But with the hydraulic separation you will need a second pump as you'll have primary and secondary circuits then.

 

 

Also, check out Graham's playlists on Samsung fault codes and how to resolve them: https://www.youtube.com/@myheatpumpchannel7577/playlists There are a few on flow rate as well.

[Ceridunn]

47 minutes ago, akjos said:

If I remember correctly, Samsungs don't have an internal pump. So you need one pump external to the unit which will run your system. I'm not sure about the latest generations though. You can easily check it by popping the lid and seeing if there's a pump in there by the water heat exchanger.

Flow rate is the most important thing of a heat pump and each needs about 2x-2.5x the capacity in l/min. So in your case (8kw), you need around 16-20l/min flow rate running always when your heat pump is on. In a simple system (no buffer, no LLH etc), you need to make sure all your UFH loops are open and the total flow rate across them matches your required 16-20l/min.

If you have zones that close, you will need either a bypass valve to make sure you have the required flow when zones close, or do hydraulic separation with a LowLossHeader. But with the hydraulic separation you will need a second pump as you'll have primary and secondary circuits then.

 

 

Also, check out Graham's playlists on Samsung fault codes and how to resolve them: https://www.youtube.com/@myheatpumpchannel7577/playlists There are a few on flow rate as well.

Hi, many thanks. I did look in the cabinet yesterday and couldn't see something that looked like a pump, was hoping it was in there just that I was too stupid to see it! 😜. Will splice the pump I have into the system, so hopefully should have something running later today. BTW I had already watched graham's video on error code 911 low flow rate, will look at a few more! Cheers

[HughF]

Samsung units need an external pump, make sure it’s a PWM one (and connect it to the pwm terminals in the Samsung cabinet) so the heat pump has control over the deltaT

[Ceridunn]

OK, pump added, it was the one supplied with my manifold, so not pwm, but it does work and now I've got the heat pump running at last. All my loops need to be open on the ufh to get 20lpm, if I close 1 loop it drops to just above 18 so for now won't be using controlled zones. Something I've noticed is the pressure on the manifold goes high, would a simple expansion vessel sort this for now or do I need to go for something more permanent like a buffer or low loss header etc( I want to have controlled zones running next winter so will make changes to allow this some time in the summer)Another thing is I've set the outlet temp at 45 degs, but it doesn't seem to want to go higher than 31, now I'm hoping I just need to make some setting adjustments so need to read through instructions again to see if I've missed anything, but if someone has any ideas to save me a little time that would be great as I'm busy tiling the  floors now. 

[PeterW]

35 minutes ago, Ceridunn said:

Something I've noticed is the pressure on the manifold goes high, would a simple expansion vessel sort this for now

Your heating circuit should already have one with a minimum of 15% of system volume - if not you are in danger of damaging the heat exchanger in the heat pump. Who designed this system..? 

 

[akjos]

Water expands as it heats up, so you definitely need an expansion vessel both on your heating circuit and your DHW.

Just search for Robokit online.

[Ceridunn]

On 07/02/2023 at 00:13, PeterW said:

Your heating circuit should already have one with a minimum of 15% of system volume - if not you are in danger of damaging the heat exchanger in the heat pump. Who designed this system..? 

 

I decided to go with ufh in my renovation then decided last minute to put this on a heat pump, so it wasn't really designed just thrown together. Initial advice was as its just ufh on the heat pump I wouldn't need buffer or anything like that. But obviously no one thought to advise on expansion vessels. The pressure has stayed within the max for the heat pump as the temp hasn't got that high yet, so will fit an expansion vessel ASAP!👍

[PeterW]

1 hour ago, Ceridunn said:

Initial advice was as its just ufh on the heat pump I wouldn't need buffer or anything like that.

Was this by a heat pump salesman..?? It all needs designing and a lot of the “just hook an ASHP to UFH” advice is badly considered and may not perform anywhere close to what it could do with a few hours design and a couple of extra components.

[joth]

3 hours ago, Ceridunn said:

I decided to go with ufh in my renovation then decided last minute to put this on a heat pump, so it wasn't really designed just thrown together. Initial advice was as its just ufh on the heat pump I wouldn't need buffer or anything like that. But obviously no one thought to advise on expansion vessels. The pressure has stayed within the max for the heat pump as the temp hasn't got that high yet, so will fit an expansion vessel ASAP!👍

The advice here sounds a bit like someone being told they don't need four wheel drive, so they only put two wheels on their car. 

 

Our (ecodan) ASHP install manual mandates many additional components, e.g. filter, pump, flow sensor, drain valve, expansion tank, PRV, temperature sensors, diverter valve (for DHW),  blending valve , safety isolation switch,  etc etc etc. 

Just because someone says you don't need X doesn't remove the need to read the manual and find the list of all the other stuff you do still need. 

 

Edited February 8, 2023 by joth

[JohnMo]

1 hour ago, joth said:

Our (ecodan) ASHP install manual mandates many additional components, e.g. filter, pump, flow sensor, drain valve, expansion tank, PRV, temperature sensors, diverter valve (for DHW),  blending valve , safety isolation switch,  etc etc etc. 

Couldn't agree more.

 

So do all manuals, but people don't read them, they know better (or not). The install manuals always have at least one system diagram, but also many variants and options in lots of cases. One thing in common, they always have a pressurised system with an expansion vessel, and safety relief valve etc. Stating clearly if included in the ASHP or not. If included also stating to calculate if a further expansion vessel is required due to system size.

 

Good job it's only a low temp heat source, at 70 degrees, something may gone bang.

[Ceridunn]

On 07/02/2023 at 00:13, PeterW said:

Your heating circuit should already have one with a minimum of 15% of system volume - if not you are in danger of damaging the heat exchanger in the heat pump. Who designed this system..? 

 

I decided to go with ufh in my renovation then decided last minute to put this on a heat pump, so it wasn't really designed just thrown together. Initial advice was as its just ufh on the heat pump I wouldn't need buffer or anything like that. But obviously no one thought to advise on expansion vessels. The pressure has stayed within the max for the heat pump as the temp hasn't got that high yet, so will fit an expansion vessel ASAP!👍

[Ceridunn]

OK, I understand I should have spent a little more time planning the system. In my defence a little, there aren't many system diagrams that deal with ufh only, they all seem to be systems that include dhw etc 

On 08/02/2023 at 11:35, joth said:

The advice here sounds a bit like someone being told they don't need four wheel drive, so they only put two wheels on their car. 

 

Our (ecodan) ASHP install manual mandates many additional components, e.g. filter, pump, flow sensor, drain valve, expansion tank, PRV, temperature sensors, diverter valve (for DHW),  blending valve , safety isolation switch,  etc etc etc. 

Just because someone says you don't need X doesn't remove the need to read the manual and find the list of all the other stuff you do still need. 

 

Hi, thanks for the comment, I have tried reading up on this but not really found much advise when connecting to ufh only. Of all the additional components you mention I did only miss the expansion tank, important though I know.