Water Pressure

[Gashead]

I have a question about water pressure. My entire house is “plumbed” with ½ inch pvc pipes. I have a mains fed water tank with a Mitsubishi WP155 pump. I would like to improve the water pressure which is just about adequate. There is a section of pipe, about 15 feet that is buried between the pump and the house. If I replaced this section with ¾ inch pipe would that have an effect on the pressure or would the ½ bottleneck beyond that negate any gains?

[bankruatsteve]

The pressure is coming from your pump. If you want more, you may need to go with "250".

[Crossy]

A two stage upgrade is needed.

1. Bigger pump.
2. Replace that length of pipe you can get at with 1".

[Gashead]

I originally had a 250 pump (assuming more power equals more pressure) but it just short cycled.

[DPGumbypgh]

The 15 ft of 1/2 pipe has a pressure drop of about 5-7 psi if changed to 3/4 inch pipe would have 2-4 psi pressure drop. The pump settings are 18-24psi . The 205 or 255 pump would give you 29-40 psi settings. If you want to change the pipe change it to 1" everywhere as cost will be about same. Better to increase the pump size if you want higher pressure at the outlet.

[sandyf]

I have a 155 pump and would say the same, about adequate. It is 3/4 inch from the pump to the house, about 15m, and then splits down to 1/2 inch for 2 bathrooms and kitchen. The first bathroom is just over the 15m from the pump and has the best pressure.

My sister in law has a 255 pump and she has a tap in the garden, used to wash the vehicles, and that is over 100m from the pump and fed by 1/2 inch pipe, the pressure from the hose would knock you over.

An increase in pump size will be much more effective than changing pipes.

[Gashead]

As I said, I originally had a 250 pump. The guy who fitted it told me that with 1/2 inch pipe it was too much. I put it in anyway and the pressure was weak as the pumped just short cycled. I took it back and got the 155 and the pressure was actually marginally better with no short cycling. Am I missing something - maybe a pump setting? I would get a new pump today if I thought it would give me what I want. The pipes are the problem and short of ripping them all out (which is not an option right now) I am looking for any help I can get. Looks like the first thing is to replace any exposed pipe with 1 inch. Maybe that increased capacity would make a bigger pump viable??

[RichCor]

You may need to add a large bladder tank to keep the larger pump from short cycling so often.

[wayned]

I have a WP-255Q2 and my house is plumbed with1/2". The farthest bathroom is about 25 meters from the pimp and if I didn't have a valve to turn down the water supply to the bum gum it would painfully blow you off the pot! My pump does not quick cycle. It sounds like you might have some restrictions in your plumbing , cut PVC pieces and globs of glue.

[RichCor]

I would think that 37 - 30 Liters/min would be adequate.

We run a Hitachi WTP100GX2 shallow-well pump on a 1/2" line servicing the two bathroom showers, kitchen and a washing machine but I ran a parallel 3/4" line from the pump to the garden where a hose can easily shoot a 6m stream of water across the garden.

Prior to replacing the pump we had an pressure issue cause by a faulty bladder in a pressure tank, causing the pump to short-cycle and pressure to oscillate wildly at the taps. Once a working pump that had a large pressure tank was installed all the issues went away.

Are you delivering to taps above 12m?

[SidFernwilter]

What you do want is the Grundfos MQ, the only thing that will work properly. A normal pressure would be 3,5 - 4 Bar or 50 - 58 psi.

[sandyf]

As I said, I originally had a 250 pump. The guy who fitted it told me that with 1/2 inch pipe it was too much. I put it in anyway and the pressure was weak as the pumped just short cycled. I took it back and got the 155 and the pressure was actually marginally better with no short cycling. Am I missing something - maybe a pump setting? I would get a new pump today if I thought it would give me what I want. The pipes are the problem and short of ripping them all out (which is not an option right now) I am looking for any help I can get. Looks like the first thing is to replace any exposed pipe with 1 inch. Maybe that increased capacity would make a bigger pump viable??

You may have some restriction in the pipe. I fitted a hose point to our deep well pump which is a 300 pump. The hose connection is the push on type which is even smaller than a half inch pipe. When using the hose the pump cycles, not enough flow to bring the pressure down for very long, but the jet from the 30m hose goes about 30/40 feet.

Have you checked your water outlets, they often have a small filter fitted that can clog up and reduce the outlet pressure. It may mean removing the tap and blowing through in the reverse direction, I often have to do this with the garden taps.

If you have an electric shower unit, the filter will be in the inlet connection.

[Gashead]

As I said, I originally had a 250 pump. The guy who fitted it told me that with 1/2 inch pipe it was too much. I put it in anyway and the pressure was weak as the pumped just short cycled. I took it back and got the 155 and the pressure was actually marginally better with no short cycling. Am I missing something - maybe a pump setting? I would get a new pump today if I thought it would give me what I want. The pipes are the problem and short of ripping them all out (which is not an option right now) I am looking for any help I can get. Looks like the first thing is to replace any exposed pipe with 1 inch. Maybe that increased capacity would make a bigger pump viable??

You may have some restriction in the pipe. I fitted a hose point to our deep well pump which is a 300 pump. The hose connection is the push on type which is even smaller than a half inch pipe. When using the hose the pump cycles, not enough flow to bring the pressure down for very long, but the jet from the 30m hose goes about 30/40 feet.

Have you checked your water outlets, they often have a small filter fitted that can clog up and reduce the outlet pressure. It may mean removing the tap and blowing through in the reverse direction, I often have to do this with the garden taps.

If you have an electric shower unit, the filter will be in the inlet connection.

[Gashead]

As I said, I originally had a 250 pump. The guy who fitted it told me that with 1/2 inch pipe it was too much. I put it in anyway and the pressure was weak as the pumped just short cycled. I took it back and got the 155 and the pressure was actually marginally better with no short cycling. Am I missing something - maybe a pump setting? I would get a new pump today if I thought it would give me what I want. The pipes are the problem and short of ripping them all out (which is not an option right now) I am looking for any help I can get. Looks like the first thing is to replace any exposed pipe with 1 inch. Maybe that increased capacity would make a bigger pump viable??

You may have some restriction in the pipe. I fitted a hose point to our deep well pump which is a 300 pump. The hose connection is the push on type which is even smaller than a half inch pipe. When using the hose the pump cycles, not enough flow to bring the pressure down for very long, but the jet from the 30m hose goes about 30/40 feet.

Have you checked your water outlets, they often have a small filter fitted that can clog up and reduce the outlet pressure. It may mean removing the tap and blowing through in the reverse direction, I often have to do this with the garden taps.

If you have an electric shower unit, the filter will be in the inlet connection.

Good point. I'll check all the outlets and see if I can detect anything. Also another good reason to replace any pipes I can, at least I'll know that section is ok. Thanks.

[Pib]

I have a WP-255Q2 and my house is plumbed with1/2". The farthest bathroom is about 25 meters from the pimp and if I didn't have a valve to turn down the water supply to the bum gum it would painfully blow you off the pot! My pump does not quick cycle. It sounds like you might have some restrictions in your plumbing , cut PVC pieces and globs of glue.

Ditto...same pump (a little over 6 yrs old)...same piping...two story house...around the same 25 meters distance.

[SidFernwilter]

A pump that quick cycle is because of a non existing air pocket in the pumps bladder or accumulator tank.