Water pressure too low to fill boiler

[TommyHoy]

We recently inherited an old house and the cold water supply comes from a private spring and is generally low in pressure (can easily stop the flow with a finger over the tap).

The property has a relatively new (< 5years old) condensing boiler.

The rads were full of air so we bled them but now we cannot refill/pressurise the boiler as the water pressure is too low - opening the valves on the filling loop achieves nothing.

We will be getting a mains water supply fitted in the coming months so don't want the cost of installing a system pump.

Any suggestions on filling the boiler?

Thanks!

 

[jackthom]

Although I haven't tried it myself it is possible if you have easy access to the expansion vessel and have a foot pump.

You'd need to remove just a little air from the expansion vessel while using the filling loop to get in as much water as possible.
Then you can use the foot pump to reinflate the expansion vessel up to the minimum required pressure.

It might be tricky to get just the right amount of air space in the vessel to allow for expansion but you can monitor the pressure as it heats up to check all is OK.

Those who have actually experimented with this may have some better advice on how to get just enough air in there. Too much is also not recommended.

 

[oilboffin]

Is your supply pumped from the spring if so it may be your pump playing up you may have a pressure vessel on the pump or a pressure adjuster on the pump.Bob

 

[algas]

try a 15mm copm bend with the nut and olive removed from one end with a short piece of 15mm copper in the other end, into the highest rad on the system then fill using a bit of hose and a funnel, it may take some time!

 

[TommyHoy]

Is your supply pumped from the spring if so it may be your pump playing up you may have a pressure vessel on the pump or a pressure adjuster on the pump.Bob

I'm not sure (it is shared with a couple of farm properties) - the flow depends on the weather (i.e. amount of recent rain) and is quite dirty when it arrives at the property before going through a cartridge filter.

try a 15mm copm bend with the nut and olive removed from one end with a short piece of 15mm copper in the other end, into the highest rad on the system then fill using a bit of hose and a funnel, it may take some time!

I think I'll give this a go to get the water in then try the suggestion below to get enough pressure to fire the boiler.

Although I haven't tried it myself it is possible if you have easy access to the expansion vessel and have a foot pump.

You'd need to remove just a little air from the expansion vessel while using the filling loop to get in as much water as possible.
Then you can use the foot pump to reinflate the expansion vessel up to the minimum required pressure.

It might be tricky to get just the right amount of air space in the vessel to allow for expansion but you can monitor the pressure as it heats up to check all is OK.

Those who have actually experimented with this may have some better advice on how to get just enough air in there. Too much is also not recommended.

 

[Madrab]

You'd need a water level at least 5m above the highest point of the system to get the min 0.5bar into it to get it running.

Buy/Hire a water pressure test pump, use that to fill, bleed and inhibit, may take a while of course.

 

[bernardgreen]

A old style Hozelock Killaspray will withstand about 1 bar of pressure. Not sure about the modern ones though.

Very easy to connect a flexible hose to the handle after the wand has been removed ( I recall a standard threaded coupler fitted ).

 

[oilboffin]

God what a supply make sure the filter isn't blocked.Bob

 

[Echo the husky]

To save time, I know you won't be able to get the pressure up, but can you fill the bulk of the system with water by opening the filling taps as well as radiator bleed valves? Or is the pressure too low even for that?!

 

[holty]

What boiler and what set up. Seen many a combi running off a boost pump for hot water and maybe cold. This would also adequetly charge the heating system up. Ps pls dont tell me its a ferolli and your place is in cornwall

 

[Mikefromlondon]

fill it up with a jet washer if you have it, connect the outlet from it to your filling loop, and let the jet washer do the job, switch off when you get to the right pressure. filling loop will also stop pressure escaping when you uncouple the jet washer, however you will need some sort of method where you can safely couple the outlet of the jet washer to the filling loop inlet coupling, it might even screw directly to your jet washer if it was held high on a chair or a stool or if your filling loop has long tail.
(not tried but i am sure it would work, just don't over pressurise it, so stop when you get 1 to 1.5 bars as required by your boiler, or overfill if you still need to bleed more ait from your rads.)

Beware pressure washers can reach very high pressures, like 110bars so don't push it for too long, it can pump 360 liters per hour or 6 liters per minute, so as long as you stop it at around 2 bars on your boiler, you are OK Its no different to like when you are inflating a car tyre from a garage compressor that has the ability to inflate a truck tyre to 200psi whilst car tyres only require around 32psi. You may only need a few seconds to fill it to 2 bars, then reduce it to what you need by bleeding from the rads.

 

[DaveHerns]

I think MFL's suggestion might be more like inflating a bike tyre from a garage compressor....

 

[Mikefromlondon]

You could say that, but we need results, not being left stuck out.
Seriously if you did have a bike and someone deflated it and you had no bike pump, or other means to inflate it, you would consider using a garage monster compressor, I have seen many kids/people take their bike to garages to inflate their tyres, you even get a special adaptor sold in bike spare shops to do so, bike tyre needs even stronger (like 90psi) pressure than car tyres. Besides all boilers have PRV to safely expel excess pressure.

You are trying to create a problem that does not exist.

 

[Mikefromlondon]

//www.diynot.com/diy/threads/forum-rules-general-info.19448/

 

[gigz]

Hire a pump from a tool hire shop.