Water pressure - possibly a very dumb question
Discussion
Went to pressure wash the patio yesterday attaching the washer to the new hose I've installed. Pressure was pretty crap and barely got the patio attachment spinning. The new hose I installed is a 30m one.....which I think is a fair bit longer than the previous hose I had......is it a case of the longer the hose the lower the pressure is going to be?
I did get it working by plugging the washer directly into the tap using a very short piece of hosepipe, although still the pressure seemed a bit lower than normal, so perhaps my general area was just down a bit on pressure?
I'm hoping it's the latter, as it's going to be pretty annoying if I can't actually use the new hose reel for the pressure washer!
I did get it working by plugging the washer directly into the tap using a very short piece of hosepipe, although still the pressure seemed a bit lower than normal, so perhaps my general area was just down a bit on pressure?
I'm hoping it's the latter, as it's going to be pretty annoying if I can't actually use the new hose reel for the pressure washer!
I know Thames Water reduced the pressure in my neighbourhood a few months ago due to leaks. They're not having much luck having caused two sink holes in the last 5yrs (both resulting in roads being closed for over a year each time, and one house to subside massively!).
It's not great but can still operate my pressure washer on a 30m hose. I have two external taps, and the one nearest the incoming supply is significantly better than the other.
It's not great but can still operate my pressure washer on a 30m hose. I have two external taps, and the one nearest the incoming supply is significantly better than the other.
It’s more a question of flow rate, though there is some connection with pressure. A hose of that length will diminish flow rate. Using the largest possible diameter and avoiding any restrictions on adapters used to attach it might help.
Broadly, a short hose to supply and a longer high pressure hose on the pumped side of the pressure washer will work better.
Broadly, a short hose to supply and a longer high pressure hose on the pumped side of the pressure washer will work better.
The faster that water flows through a pipe, the more friction it will encounter. So ... if you clamp your thumb over the end of a hose to stop the flow of water, you'll feel the pressure building up behind your thumb until it eventually reaches the maximum pressure that your supply can provide. Because you've stopped the water flowing with your thumb, there's no friction in the pipes. No movement, no friction. As soon as you let the water behind to flow a little, you'll feel the pressure starts to drop. This is because the friction in the pipes is acting like a brake and some of the pressure of the incoming supply is having to overcome that friction.
The longer your hose, the more friction there is to overcome. It could be that the friction is so high that the flow into the pressure washer is insufficient for it to work properly. That would be a little surprising, but it's possible, particularly if your washer needs a large flow rate and/or if there is anything else obstructing the flow ... e.g. one of those little in-line filters (like a tiny sieve) has got a bit gummed up, or there's an isolator valve in line with your garden tap that isn't fully open.
As others have said, you could use your hose to fill a bucket and then run the pressure washer from the bucket. If there pressure washer empties the bucket faster than your house can fill it, then your supply is definitely going to be limiting your pressure washer.
The longer your hose, the more friction there is to overcome. It could be that the friction is so high that the flow into the pressure washer is insufficient for it to work properly. That would be a little surprising, but it's possible, particularly if your washer needs a large flow rate and/or if there is anything else obstructing the flow ... e.g. one of those little in-line filters (like a tiny sieve) has got a bit gummed up, or there's an isolator valve in line with your garden tap that isn't fully open.
As others have said, you could use your hose to fill a bucket and then run the pressure washer from the bucket. If there pressure washer empties the bucket faster than your house can fill it, then your supply is definitely going to be limiting your pressure washer.
ATG said:
The faster that water flows through a pipe, the more friction it will encounter. So ... if you clamp your thumb over the end of a hose to stop the flow of water, you'll feel the pressure building up behind your thumb until it eventually reaches the maximum pressure that your supply can provide. Because you've stopped the water flowing with your thumb, there's no friction in the pipes. No movement, no friction. As soon as you let the water behind to flow a little, you'll feel the pressure starts to drop. This is because the friction in the pipes is acting like a brake and some of the pressure of the incoming supply is having to overcome that friction.
The longer your hose, the more friction there is to overcome. It could be that the friction is so high that the flow into the pressure washer is insufficient for it to work properly. That would be a little surprising, but it's possible, particularly if your washer needs a large flow rate and/or if there is anything else obstructing the flow ... e.g. one of those little in-line filters (like a tiny sieve) has got a bit gummed up, or there's an isolator valve in line with your garden tap that isn't fully open.
As others have said, you could use your hose to fill a bucket and then run the pressure washer from the bucket. If there pressure washer empties the bucket faster than your house can fill it, then your supply is definitely going to be limiting your pressure washer.
Thanks for this, very helpfulThe longer your hose, the more friction there is to overcome. It could be that the friction is so high that the flow into the pressure washer is insufficient for it to work properly. That would be a little surprising, but it's possible, particularly if your washer needs a large flow rate and/or if there is anything else obstructing the flow ... e.g. one of those little in-line filters (like a tiny sieve) has got a bit gummed up, or there's an isolator valve in line with your garden tap that isn't fully open.
As others have said, you could use your hose to fill a bucket and then run the pressure washer from the bucket. If there pressure washer empties the bucket faster than your house can fill it, then your supply is definitely going to be limiting your pressure washer.
Having used this pressure washer many time in the past successfully, I know that the flow/pressure at my house is (or at least has been) more than enough to run it. At the moment the only variable is the new longer hosepipe, although I don't think it's THAT much longer than the previous one I have used.
Starting to think maybe it was a Sunday where the whole street was using their hosepipe so maybe pressure was just lower than usual.
Maybe I'll try again this weekend.....
Worth checking, does your new hose have any quick connect fittings? The ones that automatically shut off the water when you remove the a spray nozzle or similar.
They don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
They don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
Edited by triggerhappy21 on Monday 13th April 13:17
triggerhappy21 said:
Worth checking, does your new hose have any quick connect fittings? The ones that automatically shut off the water when you remove the a spray nozzle or similar.
They don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
What ^ Said - "stop" fittings don't work well with pressure washersThey don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
B'stard Child said:
triggerhappy21 said:
Worth checking, does your new hose have any quick connect fittings? The ones that automatically shut off the water when you remove the a spray nozzle or similar.
They don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
What ^ Said - "stop" fittings don't work well with pressure washersThey don't work with pressure washers, as the negative pressure causes them to seal or partially close.
Example are the hoselock aquastop fittings, they have a red collar and cause problems for pressure washers.
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff