Help on what kind of system I have and how I can change it

[ColCol]

Hi, I have recently moved to a new house which has a system unlike anything I have seen on the internet. It has a combi boiler (bosch 532/i) which is condensing and probably fitted 2010ish. I have NO CYLINDER in the house. In the attic I have two tanks, one for the cold water to everywhere in the house including the kitchen and one presumably for the central heating system (a smaller one). And the strange bit: at the boiler I also have no mains supply. This means that when I try to refill the heating system (it regularly cuts out because the pressure falls below 1 bar) I can only get it up to about 1.1 or 1.2 bar, which means that a month later it has fallen below 1 bar again. I have one mains tap which is in the garden and seems to have loads of pressure - nothing in the house (except the mains feeder pipes to the tanks in the loft). The loft is about 6 meters above the boiler which makes me wonder what on earth is giving the pressure to the boiler when I refill the heating?
I was wanting to understand it before I do some major work on the house and get a plumber to change the system. Any help gratefully received. I need to change it so that I get some more flow in the hot water system and the shower, and so that I can re-pressurise the central heating system.

 

[Rob Foster]

So the boiler lights up and heats the hot water when you open up an hot tap instanantaneously ?. Is the hot water to the boiler coming off the cold main or from a roof tank ? maybe a diagram will help us understand whats going on. cenralheatking

 

[ColCol]

Sorry - I am being an idiot. I just crawled into the crawl space in my converted loft to access the tanks (not easy!) Both tanks are empty. the plumber has just left the whole lot there due to the difficulty of access to get them out. All the pipework is there, etc but I think its all redundant. I must be mains throughout, but the pressure at my house must be REALLY low because I am at the top of a hill. So yes, I get instant hot water from the boiler, but NO the water tanks in the loft are both empty and cold water must be coming from the mains at really low flow rates. Can mains water pressure be as low as 1.1 or 1.2 bar?

 

[SimonG]

Check your stop tap is fully open, and then turn it back a quarter turn to stop it jamming.

 

[Ric2013]

Can mains water pressure be as low as 1.1 or 1.2 bar?

Not usually, but yes it can be. If the mains pressure is low, then opening a stopcock or not will not affect the standing pressure.
Have you tried popping one of these onto your hose outlet tap to check the actual pressure? I'm not suggesting you buy it on Amazon, but it shows what I'm on about. https://www.amazon.co.uk/Monument-Mains-Water-Pressure-Gauge/dp/B0001P0F5O

 

[ColCol]

OK - thanks. I will do. The mains stopcock is fully open and all isolating valves are fully open, but the flow through some taps is very poor and the pressure at the boiler struggles to get to 1 bar (but the boiler cuts out at 0.8). thanks for help. I will close this thread now as I think I have what I need to sort things out. thanks again for your help.