JohnMo

Not really true, have you actually read many of my posts. I have run every mode possible, over the last couple of heating seasons, to get the best output per pound spent. Had a thermostat in every room (still have, but no longer connected). The best cost wise with thick screed given a large enough heat source, is batch charging the floor with gas or ASHP on TOU tariff. But my heat pump isn't big enough for that below zero. So straight WC is the next best thing. My house doesn't need, thermostats or TRVs, but like a good radiator system, the UFH loops are sized to give a equal output to heat loss expected for each room, the difference is made up by tweeking flow rate. Heat losses are low, floor temp extremely close to room temperature so the heating system responds to changes in room temp without intervention. The further the room and heater diverge from each other the more reliant you are on control. So flow temperature of 35 for radiators, is way better than a lot systems being installed at 45 to 55. A 35 deg radiator can much better vary it's output on its own in response to solar gains, than a 45 Deg one. Currently cooling the heat pump compressor ran 9 times over the last 24 hrs. Gaps between run varied from one hour to four hours, in response to room temp changes. Compressor restarts when average return temp goes above 19.8 degs. The word general makes the whole sentence meaningless. As it permits deviation and allows you not exactly follow to the letter. So wide open to interpretation. If you are to follow exactly, it would say must or shall or even should.

The document also says in the heat pump section: 6.38 The heat pump unit should include controls for all of the following, in addition to meeting the general requirements for heating and hot water systems in Section 5. 6.39 The heat pump should have external controls that include both of the following. a. Weather compensation or internal temperature control. b. Timer or programmer for space heating So for a heat pump you can either have room controls or WC. The timer or programmer normally comes with the heat pump or a timer thermostat can be used as overheat protection.

It tap water going through an Ion Exchange resin in a 10" filter housing. The water that came out was brown and although had glycol it has obviously had picked some corrosion from a carbon steel buffer I had in the system. The water circulating is correctly sitting at 168ppm dissolved solids and 341 micro seimens conductivity. pH is about 7.3, but this should move over time to about 8. Have a slip stream through the resin, setup which I am going to run again tomorrow for a few hours, the aim is to get the ppm down below 150.

Looking at images they look more suited to dry lining, than plaster on plasterboard. Curved edge and recess, could look naff.

Interesting question. I read the Scottish building regs compliance notes 2022. And also came Kent Council compliance notes. Both say For all boiler types except heat pumps, it makes very detailed mention of individual room temp control and thermostats or trv's and time controls, multiple zones etc. For heat pumps it states (Scottish) • weather compensation or internal temperature control • timer or programmer for space heating No mention of zones at all. (Kent) External controls should include: • room thermostat to regulate the space temperature and interlocked with the heat pump unit operation; • timer to optimise operation of the heat pump. Scottish compliance notes also mentions MIS 3005, which makes no mention of trv's. So don't believe current regs drive the use of trv's, certainly not in Scotland. In England the use of the singular (thermostat) as opposed to the plural could be just the heat pump controller.

I have just taken out the glycol on my system and now using VDI2035 (straight water with testing). Without any other changes the water flow rate jumped from 1m³/h to 1.3m³/h. So glycol slows the system right down.

Basically started flushing yesterday by slowly pushing out the old heating water with demin (ion exchange) water at a rate of around 1L/min. The old stuff was brown and smelling very unhealthy. When I stopped last night is fully clear, but you could still smell the glycol. System was left to circulate overnight. This morning. Moved to having the ASHP circulation pump on and slip steaming demin (ion exchange) water in, so 1 litre in 1 litre out, this morning and got the water to just better than tap water. Checking tap water and circulation water at the same time. Tap Dissolved solids 180ppm Conductivity 380 microsiemens Circulation water Dissolved solids 166ppm Conductivity 320. Now have a side stream set up to push circulation water into the ion exchange filter, without adding new water. Aiming for below 150 ppm dissolved solids or below - currently at 166 compared to tap water of 180 ppm. Using a simple garden hose flow meter from B&Q. One thing that surprised me was the effect on system flow rate. Nothing had been changed except the fluid pumped, it is now straight water. Prior to clearing the glycol mix from the system, it was circulating 1m³/h, this morning just below 1.3m³/h. So a question Do I leave the flow rates high or adjust the UFH manifold rates down to bring overall rate down?

Plus you have to run mixer and another pump due to the flow temperature difference. Unless you do dT15 radiators and flow a max of 35 degs

So you pay to do the fiddly expensive stuff. MCS installer comes along runs to pipes from heat pump to your stuff, will say you need to change this that and other, because it's not how he would do it, pockets £7500 and charges you a couple of grand for being there. If you can run pipe you can install a heat pump. Just keep everything really simple. But it's just as @Dave Jones says.

Or a heat pump that delivers 7kW at your design flow temp and your outside air design temperature. Plus an allowance to heat DHW. Allow 2 hrs for DHW, would require the heat pump to be able to provide heat to home in 22 hrs. So (7x24)/22=7.6kW.

What do your drawings state? That is the builders go to document. If they haven't built to drawing, the build is wrong. It is the builders responsibility to fix and make good, so your build complies with the approved drawings. In planning you are only allowed to build to the agreed specifications, deviation requires approval.

I guess £10K plus your grant.

Just any old doors as long as they are steel or a particular style?

Sound like a spaniel cross with another dog.

How do you call for heat when heating? If you are using a buffer the call for heat may come that, if so you need to change it's temperature activation temperature. If you are using house thermostat(s) then you need to wind them above your actual room temperature so they call for heat. If you using radiators don't waste your time. Just because you have enabled cooling, doesn't mean the heat pump will do anything. It needs a call for heat or cooling to start.

It seems to have only two distinctions in the article 1. PH approved 2. Cheap brands that are poorly insulated. There is a lot of middle ground missing from the article, PH certified isn't the be all, ends all of equipment. The Titon units are neither a cheap brand nor are they poorly insulated. So missing entirely from the comparison made in the article. "How do you compare" you research, you buy cheap brands (you can pay cheap prices), make your choice, then get on with life. Inside a Titan HRV10 - a huge chunk of insulation, within a metal box, very tight fitting filters and heat exchanger. It's a huge unit and the large HE looks small but it's pretty big.

Would second that.

I would go on to the grant website and read all the rules for yourself and then you know what is correct.

Remember there is a time limit from grant approval to commissioning being complete.

Slight typo - vented should read unvented, for anyone else reading

But for best gas economy you would size them the same, to get best of the condensing mode.

Got my meter today, similar size to a smart phone, so you don't need your glasses on the read the digits. Just tested some tap water Conductivity is 305 microsiemens Scales produced (dissolved minerals) is 145 ppm. So my tap water comes in fine. But higher than I would like, so will be treating it. Ran tap water through the ion exchange resin, it seems to drop the dissolved minerals to about 45 ppm and half the conductivity to 150 microsiemens. A bit of playing with flow rates required to see how it changes. Have added a cheap hose pipe flow meter, then I can repeat a flow rate and also see the quantity of water I have, flushed out or added to system.

Start with basics Look at your name plate on the hot air heating system - what is it's rated output in kW. If it well below 14kW the quote you received is a bit of a joke. I would suspect closer to 6 to 8kW. Have a look on this forum, there have been people replace the hot air heat with A2A heat pump, so no radiators required.

Add 0.3 to number of air changes per hour and change MVHR efficiency to 0%.