Heat Pumps - post here.

JonMac

I used his data in the TA and the BER. The assessor classified the building as 180 kWh/m2/yr.
He gave the heat loss area of the walls, roof, floor and windows as 310 square metres. This gives 55,800 kWh per year, or 6.4 kW per hour on average all year long.

Calahonda52

JonMac wrote: »

I used his data in the TA and the BER. The assessor classified the building as 180 kWh/m2/yr.
He gave the heat loss area of the walls, roof, floor and windows as 310 square metres. This gives 55,800 kWh per year, or 6.4 kW per hour on average all year long.

As an exercise in * and /, yes it does "give": but it's a useless exercise.

What you do need to know is
what Delta T
and what
seasonal run hours
were used to arrive at the 180
You also need to know what the ventilation heat losses are so what volume was used in the math.

Dardania

Calahonda52 wrote: »

Dis you get an SR 50 calc done to size the rads, I have a guy in Tullamore who might do it but the design needs to be right first.

I didn't...but good next step. From looking at:
https://www.housing.gov.ie/sites/default/files/publications/files/tgd_l_dwellings_2019.pdf

it appears the current version is still the draft from 2010?:
https://www.scribd.com/document/246031037/Sr-50-2010-Code-of-Practice-for-Building-Services-Part-1-Domestic-Plumbing-Heating

?

sydthebeat

Shefwedfan wrote: »

How do you do a technical assessment and then not recommend the heat pump? bit of a get out of jail card that one isnt it

Because the output of the heat pump must suit the type of heat emitter ie rads.

Standard steel rads would need a stronger heat pump running at higher flow temps than low temp alu rads running at mid ranges.

So the person who is supplying the rads (ie the plumber) should do, or have done, the SR 50 calculations to equate the heat pump size to the required rad outputs

I'm sure the assessor would have no problem specing the HP after the SR 50 calcs are carried out

JonMac

"As an exercise in * and /, yes it does "give": but it's a useless exercise.

What you do need to know is
what Delta T
and what
seasonal run hours
were used to arrive at the 180
You also need to know what the ventilation heat losses are so what volume was used in the math"

OK, but all he would say to me was "don't worry." He is a registered SEAI technical assessor, albeit much less the helpful.

I'm thinking the gas boiler was running at 13kW, so I should match that.

Calahonda52

See attached.

JonMac

See attached.

Thank you for trying to help me. I'll have a good look at those files - this is my first time at this.

Our house is 2005 timber frame with UFH; 14 loops in 4 zones. I'm just trying to replace the gas boiler with a comparable power heat pump.

This is the response I got from the Technical Assessor: "I wouldn't be able to correctly size the unit. The Technical Assessment should be able to clarify that for him."
Have you any idea what he means? I find him very hard to work with, although he loved the fee I paid.

Calahonda52

If the gas system is still in use and it is comfortable, then measure the flow and return temps on some of the loops, this is a critical piece of intel as they may have designed it on a "higher" temp, given that they needed to cool down the gas heated water.
The other thing to note is the circulation pump details..

HPs work best on the lowest possible uplift so it may turn out that you need one of the more expensive HPs that facilitate a higher flow and return.
If the unit is undersized, the outside unit will freeze up.

Have you room for a buffer tank?

JonMac

The plumber is recommending a Samsung unit with a Joule Smart Plumb Heat Pump cylinder, which has 60l buffer tank.

thos

Hi,
I've got a Daikin air 2 water heat pump, water pressure currently showing at 1.6 bar.
Can anyone give me a high/low figure for what the pressure should typically be?

Thanks,
Tom

Calahonda52

thos wrote: »

Hi,
I've got a Daikin air 2 water heat pump, water pressure currently showing at 1.6 bar.
Can anyone give me a high/low figure for what the pressure should typically be?

Thanks,
Tom

Why the question?

thos

Calahonda52 wrote: »

Why the question?

Because I've forgotten what they told me initially and I'd like to keep an eye on it

ShanE90

Usually filled to 1 - 1.5 bar when cold, when heated pressure will increase when operating to 1- 2 Bar. PRV will operate at 3 bar

thos

ShanE90 wrote: »

Usually filled to 1 - 1.5 bar when cold, when heated pressure will increase when operating to 1- 2 Bar. PRV will operate at 3 bar

Thanks!

JonMac

Samsung Gen 5 Hot Water
I had posted this in the wrong section:
I've just had an A2W system installed. The ads and the manuals say it should cycle the hot water between 43 and 48 degrees.
This one turns on the heat pump at 41.4 and turns off at 46.4. I know that doesn't sound like much of a difference but the other day I had to boil a kettle to bring the bath temperature up!
When the technician from Joule was here on Monday to commission it I asked him to sort it out but he wasn't able to.
Has anyone else seen this problem?
Should I contact Joule or Samsung or just let it go?
Thanks.

Calahonda52

its there not a boost button to bring it to 60+ on a regular basis?
have u tried setting the temp to 49 or 50 on the control panel, find the youtube video

JonMac

On the Samsung you can get the immersion to supplement the heat pump.
I don't want to do that as the heat pump itself isn't functioning properly in the first case.
The rep told me to increase the set point for hot water from 48 to 50 but it made no difference.
This unit is not working as advertised!

JonMac

This is how it is supposed to work;
Factory set, if the hot water set temperature is set to + 48C the unit will start heating the cylinder when the temperature drops 5C below set point (43C), it will heat the cylinder until 2 degrees above set point or 50C.
The highest temperature I've seen is 46.4.

JonMac

I didn't buy a heat pump so I could use an immersion heater for our bath water!

Calahonda52

JonMac wrote: »

I didn't buy a heat pump so I could use an immersion heater for our bath water!

That is NOT what is being suggested here: the boost option is required to cater for legionella.

JonMac

\Understood.
"its there not a boost button to bring it to 60+ on a regular basis?"
Yes, but not to meet the advertised performance.

Calahonda52

JonMac wrote: »

\Understood.
"its there not a boost button to bring it to 60+ on a regular basis?"
Yes, but not to meet the advertised performance.

Thanks, understood

Where is the stat you refer to? could be a faulty stat?

Have you any way of controlling the flow/return rate to the cylinder.
Thinking about the heat transfer, if the return temp is too high, due to too high a flow rate and not sufficient time to heat transfer in the tank, maybe the stat cuts out too soon ?
Could be 100% + wrong here .

ShanE90

JonMac wrote: »

I didn't buy a heat pump so I could use an immersion heater for our bath water!

What is the model of the cylinder unit/tank and outdoor unit

JonMac

I bought Joule's package of the Samsung AE160JXYDEH/EU and the Smart Plumb Heat Pump 200+60l.

Still waiting for Joule to respond. On Wednesday they told me to change the set point from 48 to 50; the system still turned off at 46.4.
I think it is a fault in the control unit.

JonMac

"Have you any way of controlling the flow/return rate to the cylinder.
Thinking about the heat transfer, if the return temp is too high, due to too high a flow rate and not sufficient time to heat transfer in the tank, maybe the stat cuts out too soon ?"

I don't think there is anything wrong with the heat pump itself. Something in the control unit is turning it on and off indepently of the set point.

I'd like to know if other Samsung owners have seen this problem.

sydthebeat

Who finds a bath at 46 degrees to be too cold??

JonMac

You missed my point. The system as is turns on the heat pump at 41.4. If you draw the bath near the low end of the cycle the bath is way below body temperature by the time it is filled.

The highest cylinder temperature I have seen is 46.4. It should be going to 50.

ShanE90

I’m not familiar with the joule cylinder setup but can you check to see if the DHW sensor is fully in its pocket and not in the top pocket
( if there are a few )

Also check that it’s not mixed up with a flow return sensor ...take it out hold yout hand on it to check, can you read the thermistors from the controller while in DHW mode ?

200 l of 50degc water should mix to around 300l for showering /bath at 38, even 45deg mixed should be enough to fill a bath.

JonMac

There is only 1 top pocket, it is fully inserted.
I have to say 200l of 41.4 water is not OK for a bath!

Tazzman

Not sure if this is the right place to post but, has anyone experience with a rapax heat pump water heater or similar?

Looking to replace an immersion for on demand hot water and possibly allow fo solar PV down the line.