Jeremy Harris Posted November 2, 2018 Share Posted November 2, 2018 8 minutes ago, joe90 said: None of the diagrams for my ASHP show a bypass valve and I cannot find a reference to one within the ASHP. As I have a diverter valve not two two way valves there should be no time that flow restriction will occur?. Answers on a post card to......... My guess is that you don't need one at all, as your system always has either the buffer tank or the DHW tank connected, so there's never a restriction. I needed one as our buffer tank is shut off when the system is in cooling mode, and the UFH valve takes a few seconds to open, during which the ASHP senses the flow restriction and shuts down with an alarm, then restart again around 20 seconds later. 1 Link to comment Share on other sites More sharing options...
Gav_P Posted November 2, 2018 Share Posted November 2, 2018 1 hour ago, JSHarris said: My guess is that you don't need one at all, as your system always has either the buffer tank or the DHW tank connected, so there's never a restriction. I needed one as our buffer tank is shut off when the system is in cooling mode, and the UFH valve takes a few seconds to open, during which the ASHP senses the flow restriction and shuts down with an alarm, then restart again around 20 seconds later. I’ve got a 3 minute delay between signal to the 2 port valves (which trigger the circulation pump) and the ASHP. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 2, 2018 Share Posted November 2, 2018 12 minutes ago, Gav_P said: I’ve got a 3 minute delay between signal to the 2 port valves (which trigger the circulation pump) and the ASHP. If the ASHP only fires up after the valve are all open then there shouldn't be a problem. Link to comment Share on other sites More sharing options...
joe90 Posted November 5, 2018 Author Share Posted November 5, 2018 On 02/11/2018 at 09:52, joe90 said: question. Is the three way valve normally sitting to provide Heating then “on” (powered up) when wanting DHW. (This is what I would have thought). 1/ Can I ask that question again. As mine appears to be working the other way, heating means three way valve is powered to supply water to A 2/ The three way diverter valve IS plumbed the right way round ( A for heating, B for DHW) I am about to re set all the parameters on the command unit but I am slowly getting my head around this now. (I am stuck indoors as I have injured my hand ?) Link to comment Share on other sites More sharing options...
Gav_P Posted November 5, 2018 Share Posted November 5, 2018 Just took a quick look at the danfoss website and it could be NO=DHW? i looked only work computer hence the rubbish image.... you don’t have a mid-position valve by any chance do you? Link to comment Share on other sites More sharing options...
Gav_P Posted November 5, 2018 Share Posted November 5, 2018 https://assets.danfoss.com/documents/DOC222386403689/DOC222386403689.pdf Link to comment Share on other sites More sharing options...
joe90 Posted November 5, 2018 Author Share Posted November 5, 2018 1 hour ago, Gav_P said: you don’t have a mid-position valve by any chance do you? No. Thanks Gav, your diagram shows powering the diverter valve means hot water to DHW. Still trying to work out what’s wrong? 1 Link to comment Share on other sites More sharing options...
Gav_P Posted November 5, 2018 Share Posted November 5, 2018 Does it? I thought that closing the circuit meant sending water to A (heating), opening the circuit returns it back to B (DHW). Link to comment Share on other sites More sharing options...
joe90 Posted November 5, 2018 Author Share Posted November 5, 2018 4 minutes ago, Gav_P said: Does it? I thought that closing the circuit meant sending water to A (heating), opening the circuit returns it back to B (DHW). Ah, yes it does (brain freeze, your diagram is opposite to my setup, I.e. my heating is on the right and DHW on the left). That seems counter intuitive as I would have thought heating would be on longer than DHW so 3 way valve would be energised for shorter periods. That will teach me to make assumptions. 1 Link to comment Share on other sites More sharing options...
joe90 Posted November 5, 2018 Author Share Posted November 5, 2018 Trying to test this but I don’t get a constant hot temp from the heat pump to see what pipes are getting hot, command unit says the compressor is running???, could this be a refrigerant problem with the heat pump? Unfortunately I have to go away for 24 hrs now so turning it off and resting my brain. Link to comment Share on other sites More sharing options...
Gav_P Posted November 5, 2018 Share Posted November 5, 2018 How long does it run for before dropping off temp? Link to comment Share on other sites More sharing options...
joe90 Posted November 6, 2018 Author Share Posted November 6, 2018 On 05/11/2018 at 17:13, Gav_P said: How long does it run for before dropping off temp? Didnt time it but about 10 min, now I am back home I will investigate again tomorrow. Link to comment Share on other sites More sharing options...
Gav_P Posted November 7, 2018 Share Posted November 7, 2018 (edited) So what’s the story? Is it behaving itself now? Edited November 7, 2018 by Gav_P Link to comment Share on other sites More sharing options...
joe90 Posted November 7, 2018 Author Share Posted November 7, 2018 Not got back home yet, I plan to start on it Thursday , will update. Link to comment Share on other sites More sharing options...
joe90 Posted November 8, 2018 Author Share Posted November 8, 2018 Just got back and started again!!!. With the control unit set up I can get it to “deliver DHW” and the pipework gets slightly warm but not as hot as I would expect ? It appears the three way valve works the wrong way round, this from Honeywell installation instructions “The valve MUST NOT be fitted on the return pipework under any circumtances. Flow from the boiler must be connected to port AB, the radiator circuit to port A and the hot water cylinder circuit to port B.” however on mine when DHW is called for the three way valve operates but the “warm” water goes to A (heating not DHW) hence the original reason I thought the three way valve was the wrong way round. am I going mad? Link to comment Share on other sites More sharing options...
ProDave Posted November 8, 2018 Share Posted November 8, 2018 Concentrate first on why the water is "warm" not "hot" What does the display say? does it say it's heating water or heating? If it thinks is is doing heating it will only be warm (and the valve will be in the correct position) Link to comment Share on other sites More sharing options...
joe90 Posted November 8, 2018 Author Share Posted November 8, 2018 10 minutes ago, ProDave said: Concentrate first on why the water is "warm" not "hot" What does the display say? does it say it's heating water or heating? If it thinks is is doing heating it will only be warm (and the valve will be in the correct position) To get things “going” I forced it into DHW mode but because the three way valve works backward it successfully charged the UFH buffer tank! And finally appeared to get hot. ?. I have changed the water temp (heating) to 35’ and manually set the three way valve open so will see if it heats the buffer when it’s temp drops. I am leaving the DHW tank on immersions as I will get it in the neck if SWMBO has a cold shower?. its the three way valve working backward that has foxed me, I have asked my plumber friend if he can spare me an hour next week to get his take on this. i am relieved however that my Ebay special ASHP is working and it’s just the controls that are playing silly buggers. 1 Link to comment Share on other sites More sharing options...
ProDave Posted November 8, 2018 Share Posted November 8, 2018 As I say concentrate on getting "hot" water regardless. If as you say the valve is operating the wrong way, then it would heat your heating buffer tank "hot" rather than "warm" when you are demanding "hot" water. If it does that then you are a step closer and the valve operation is something else to work on later. Is there a temperature probe in the HW tank? if so with the immersion on, the tank will be hot and the heat pump won't heat the hot water any more. 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 8, 2018 Share Posted November 8, 2018 There are two ways of controlling DHW temp with these units, either use dry contact controls and use a tank stat to both deselect DHW mode and also turn off the ASHP, or just let the ASHP flow temp control the DHW tank temp. Either will work OK. In my setup I have a tank stat set midway up the buffer (which in my case is used just to preheat DHW) and I use that to control relays to operate the dry contact inputs. I have my controls set so that the DHW buffer heating takes priority over floor heating or cooling, and I don't use the valve control output of the ASHP to switch the buffer in and out of circuit, but do that with a separate 12 V motorised valve. If opting to use dry contact control (which I think is the simplest way) then you can just follow the Kingspan wiring diagram, as that allows DHW to have priority. 1 Link to comment Share on other sites More sharing options...
joe90 Posted November 8, 2018 Author Share Posted November 8, 2018 Question, if I set the heating water temp to 40’ and this heats the UFH buffer tank, will the ASHP switch itself off when it has reached this temp? Or will it require a tank stat to tell it to power off? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted November 8, 2018 Share Posted November 8, 2018 33 minutes ago, joe90 said: Question, if I set the heating water temp to 40’ and this heats the UFH buffer tank, will the ASHP switch itself off when it has reached this temp? Or will it require a tank stat to tell it to power off? The ASHP will modulate down, then turn on and off as required to maintain the flow temperature at 40 deg C. In practice this isn't a problem at all, as there is hysteresis on the ASHP flow sensor, so it won't turn back on again until the flow temperature has dropped a bit. I don't have any controls on mine - if the UFH is calling for heat the heat pump is just switched on and runs at 40 deg C, modulating or turning itself on and off as required to maintain that flow temperature. It's no different to a combi boiler, they control temperature in a heating circuit the same way. If the room stat calls for heat the boiler turns on and heats to the set flow temperature, then modulates down to try and hold that as the heating demand drops, then turns off until the flow has cooled a bit before turning back on again. 1 Link to comment Share on other sites More sharing options...
Gav_P Posted November 8, 2018 Share Posted November 8, 2018 4 hours ago, joe90 said: however on mine when DHW is called for the three way valve operates but the “warm” water goes to A (heating not DHW) hence the original reason I thought the three way valve was the wrong way round. am I going mad? Are you certain that your system is calling for DHW or heating? If there is any doubt, why not just test where the heat is going by linking out across the terminals in the ASHP for heating (no. 3 and 6 IIRC). And then do the same for heating (no. 13 & 15 possibly). Also have you got a link between terminals 3 & 7? Link to comment Share on other sites More sharing options...
Onoff Posted November 8, 2018 Share Posted November 8, 2018 (edited) 4 hours ago, joe90 said: Just got back and started again!!!. With the control unit set up I can get it to “deliver DHW” and the pipework gets slightly warm but not as hot as I would expect ? It appears the three way valve works the wrong way round, this from Honeywell installation instructions “The valve MUST NOT be fitted on the return pipework under any circumtances. Flow from the boiler must be connected to port AB, the radiator circuit to port A and the hot water cylinder circuit to port B.” however on mine when DHW is called for the three way valve operates but the “warm” water goes to A (heating not DHW) hence the original reason I thought the three way valve was the wrong way round. am I going mad? Is that a 3 way diverter valve as opposed to a mid position one? What model btw? Edited November 8, 2018 by Onoff Link to comment Share on other sites More sharing options...
Gav_P Posted November 8, 2018 Share Posted November 8, 2018 @Onoff I think @joe90 said it was not a mid position above somewhere. It’s a danfoss valve I believe.. as per the document I linked above. Link to comment Share on other sites More sharing options...
Onoff Posted November 8, 2018 Share Posted November 8, 2018 1 minute ago, Gav_P said: @Onoff I think @joe90 said it was not a mid position above somewhere. It’s a danfoss valve I believe.. as per the document I linked above. He says Honeywell above. I'm only asking as I've one (a Honeywell) to fit. I'm going to run it on the bench so I make bloody sure I know how it ports. 2 Link to comment Share on other sites More sharing options...
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