LSB Posted January 1, 2021 Share Posted January 1, 2021 Good Evening and Happy New Year My next question for estimation. Once I have listed everything that I think that we need and got my approximate estimate I shall send off, but right now I'm listing everything and pricing it myself, this is what covid does to you when you can't go to the pub. My single storey barn conversion has a flat roof so there will not be any form of header tank, there will be an emersion tank in the utility room. We will have 3 showers for which I need pumps. But, all the ones I look at say 'gravity fed', which sounds to me like they need a higher tank. These pipes will need to be horizontal, one at 2m, one at 12m and one at 25m, all from the DHW tank. It is very rare that multiple showers are used at the same time, but not impossible. I'm not worried about the hot water, we have 2 showers with pumps in the existing house and it has not been an issue waiting for hot water. My issue is that I don't know what type of pump I need. I know one of ours needed replacing recently, at about £200. The existing pumps are on the same level as the showers by the tank, but we do have a cold water header tank and I'm not sure if this makes any difference. Do I need the same as we have now. TIA Jill Link to comment Share on other sites More sharing options...
PeterW Posted January 1, 2021 Share Posted January 1, 2021 Why do you need pumps ..? No tanks means everything will be mains fed - so Unvented Cylinder - so you will have all water hot and cold at mains pressure. Also are you saying your DHW heat source will be E7/Immersion heaters..? What about space heating ..? Link to comment Share on other sites More sharing options...
LSB Posted January 1, 2021 Author Share Posted January 1, 2021 1 minute ago, PeterW said: Why do you need pumps ..? No tanks means everything will be mains fed - so Unvented Cylinder - so you will have all water hot and cold at mains pressure. Also are you saying your DHW heat source will be E7/Immersion heaters..? What about space heating ..? We are planning on UFH with ASHP & Solar Panels and then just to be extra sure a backup oil boiler (no gas here). I thought we needed pumps because of the water pressure we require. We sometimes use our current tank emersion element if we need hot water quickly and don't want to wait for the boiler to do it. I'm not a plumber and have very little knowledge in this area so please be gentle with me. As we have pumps now (one per shower) to get the water pressure we need then I assumed that we will need one per shower in the build. We have very limited ridge height (thanks LPA) and it's not high anyway, hence no attic space. The roof is slightly sloped so the pipes will go in the highest bit, but all machine type things will be in the utility room. Link to comment Share on other sites More sharing options...
Gav_P Posted January 1, 2021 Share Posted January 1, 2021 Assuming you have decent mains water pressure, then exact as PeterW said.. you just need an unvented cylinder as this will deliver hot water at mains pressure. Link to comment Share on other sites More sharing options...
PeterW Posted January 1, 2021 Share Posted January 1, 2021 5 minutes ago, LSB said: We are planning on UFH with ASHP & Solar Panels and then just to be extra sure a backup oil boiler (no gas here). I thought we needed pumps because of the water pressure we require. We sometimes use our current tank emersion element if we need hot water quickly and don't want to wait for the boiler to do it. I'm not a plumber and have very little knowledge in this area so please be gentle with me. As we have pumps now (one per shower) to get the water pressure we need then I assumed that we will need one per shower in the build. We have very limited ridge height (thanks LPA) and it's not high anyway, hence no attic space. The roof is slightly sloped so the pipes will go in the highest bit, but all machine type things will be in the utility room. ok so one at a time .. CapEx of an oil boiler plus ASHP - pick one and stick to it as both don’t work together as one is low grade heat and the other is high grade heat. They need different set ups, installs and controls and you’d be better with just having ASHP with Immersion backups (UVC and Buffer tanks) as you will never use the oil and that will be £5k in the bin. You probably have boosters today as you have tanks in the attic and they give crap pressure - 0.5-0.8bar at best. As long as you have decent mains pressure then you don’t need anything further. If mains pressure is low then you need to budget for an accumulator and pump, and that’s budget the money and the space. First step is find out your static and dynamic water pressure, and what sort of flow you’ve got. Does the plot have its final water supply installed or are you having a new supply ..?? Link to comment Share on other sites More sharing options...
LSB Posted January 1, 2021 Author Share Posted January 1, 2021 11 minutes ago, PeterW said: ok so one at a time .. CapEx of an oil boiler plus ASHP - pick one and stick to it as both don’t work together as one is low grade heat and the other is high grade heat. They need different set ups, installs and controls and you’d be better with just having ASHP with Immersion backups (UVC and Buffer tanks) as you will never use the oil and that will be £5k in the bin. You probably have boosters today as you have tanks in the attic and they give crap pressure - 0.5-0.8bar at best. As long as you have decent mains pressure then you don’t need anything further. If mains pressure is low then you need to budget for an accumulator and pump, and that’s budget the money and the space. First step is find out your static and dynamic water pressure, and what sort of flow you’ve got. Does the plot have its final water supply installed or are you having a new supply ..?? We will be having a new supply, currently the barn has water from our house so I haven't looked into this yet. The barn is 120m from the water hydrant (opposite side of road) up a slope totally about 5m, so I can't imagine that we will have very good water pressure, although the 2 taps are not too bad just through a pipe we put in 20 years ago. When the barn was used for pigs it had a huge water tank, like a petrol tanker size, raised on a brick built platform, I assume for water pressure. But, there was up to 2,000 pigs in an intensive breeding unit so they needed lots of water. Rules changes, pigs gone, house sold at auction to use about 2 years later, that was 20 years ago. So, I don't know how I can find out what the water pressure will be, can the water board tell me ? If I needed to budget for an accumulator and pump what specification would those be, then I can add this to my estimate as I'm looking at worst case cost to start with. Link to comment Share on other sites More sharing options...
Gav_P Posted January 1, 2021 Share Posted January 1, 2021 10 minutes ago, LSB said: When the barn was used for pigs it had a huge water tank, like a petrol tanker size, raised on a brick built platform, I assume for water pressure. But, there was up to 2,000 pigs in an intensive breeding unit so they needed lots of water Isn’t that more because pigs need a high amount of water regularly. I think that 8 hours or something without water has a significant impact on them. So the tanker was more for emergency storage than pressure. Link to comment Share on other sites More sharing options...
PeterW Posted January 1, 2021 Share Posted January 1, 2021 Tank will have been for flow not pressure. 120m distance and 5m head isn’t a problem - is the current house on the same main ..?? You could start from measuring there. Outside tap or one direct off the main is the place to start. Check the standpipes too as they will give a good indication of pressure but not flow depending on pipe size. You should budget to put in a 25mm if you’ve got over 4 bar at the road, or 32mm if you have less than that. You’ll also need a decent flow - upward of 20 l/min is ideal. An accumulator can go outside in a shed, but they are quite bulky. 450 litre accumulator is around £500 so double that to cover install etc. What size hot water tank have you planned and how much plant space have you got ..? Link to comment Share on other sites More sharing options...
LSB Posted January 2, 2021 Author Share Posted January 2, 2021 12 hours ago, PeterW said: Tank will have been for flow not pressure. 120m distance and 5m head isn’t a problem - is the current house on the same main ..?? You could start from measuring there. Outside tap or one direct off the main is the place to start. Check the standpipes too as they will give a good indication of pressure but not flow depending on pipe size. You should budget to put in a 25mm if you’ve got over 4 bar at the road, or 32mm if you have less than that. You’ll also need a decent flow - upward of 20 l/min is ideal. An accumulator can go outside in a shed, but they are quite bulky. 450 litre accumulator is around £500 so double that to cover install etc. What size hot water tank have you planned and how much plant space have you got ..? Current house is opposite side of the roadside to the main, but slightly higher, so I would say main inlet is about 4m distance and 1m up. How do I measure the water pressure, we have an outside tap very near where the water comes into the house. I haven't even thought about size of tank, utility / plant room is 4.07m * 3.8m so 15.5 m2, although we do want a toilet in there in a cubicle. Also need the gubbins for ASHP, CU's washing machine, tumble dryer (can be stacked). I've also allowed for a shower, but that's more for the dog than us, just designed for where we get very grubby and don't want to trapse through the house, but again isn't essential. I haven't allowed for an airing cupboard, which is where our current tank is, but I could just lose a bit from one of the spare bedrooms for that if it is a better solution. It's great that I'm only planning for the inside so things can be changed, but it's quite scary thinking about everything that needs considering when I'm not yet sure about lots of things. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2021 Share Posted January 2, 2021 @PeterW I think you need to explain what some of the terms actually men i.e. low and high grade heat (crap terms), dynamic and static pressure. Also what can be expected and useful, rather than ideal. (something for that basic plumbing blog) Link to comment Share on other sites More sharing options...
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