Booster Pump Issues

[waterman]

Hi all...I'm the new guy here..

We recently had a grundfoss booster pump installed because of poor pressure in bath rooms. Man, it works good!!!

However, a couple of other issues have reared their ugly heads...

1- the tp valve on the gas water heater has dripped since, it actually cut loose while sleeping one nite and floode the basement. I replaced it twice and it still drips. I'm certain it has to do with the new pump but what is my best option for fixing this?? an expansion tank?

2- we have a whole house water filter and an iron remover system. The filter becomes very dirty very quickly ( a week or less) and at certain times I notice the water level in filter drop halfway and then come back up. The new pump seems to be pulling lots of junk out of the iron system, this is what's dirtying up the filter so quick. Why is the water level droping in the filter?? We actually loose the pressure from the new pump when this takes place.

Any advice will be appreciated!!

[DuneMe]

I wouldn't think you need an Expansion Tank but, is your piping system intense? Probably just need a new T&P. But (again) I am a big proponent of Expansion Tanks. However, you should only need one if your system has a lot of piping to it.

Oh, I have one of these so, great experiance with Grundfos. . .

http://compare.ebay.com/like/380159518634?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

or

http://www.faucetdirect.com/index.cfm?page=search:browse&term=Grundfos+Comfort+System

[HayZee518]

if this pump is in the hot water feed pipe, you don't need an expansion tank. first of all, is your system a continuous loop hot water system? by this I mean does the hot water go all around your house and return to the tank? at each tap, shower, lav sink, kitchen sink, dishwasher are there taps off the loop?

[LazyPup]

Water is at maximum density at 39degF and if heated or cooled it expands.

Normally as the water in a water heater expands the increased volume is offset by a small portion of the water in your system backflowing out your supply line and back to the street main.

If a PRV (Pressure reducing valve) or a Boost pump is installed they introduce a backflow preventer on the line which will not allow the excess volume to backflow, therefore when either a PRV or Boost pump is installed you are required to install an expansion tank on the water heater cold water line.

[waterman]

DuneMe, thanks for your reply...I have replaced the tp twice since the pump install..I'm thinking that's not it. Thinking about an expansion tank now. I had no idea this would cause so many problems!!

[waterman]

LazyPup, thanks for the technical info...sounds like I'm buying a tank..any idea's on why my water filter is drawing down at certain times?

[waterman]

HayZee518, thanks for the responce, but my system is not a closed loop

[HayZee518]

another thought on the booster pump -- that your lines are too small for the volume you want. feeds to the water heater and lines off the tank should be a minimum of 3/4 copper. take offs are 1/2 inch. at the lav sink and kitchen sink, they're further reduced to 3/8 inch compression. at the shower they feed directly with 1/2 inch into the shower valve. the TP valve may be leaking because of the pressure the pump is presenting to them. another thought is the pump operates all the time. what provisions do you have to start the pump if it is not running constantly? flow switch? pressure switch?

[waterman]

The booster pump only runs when there is a demand for water..seems to work fine in that regard...pipes are sized correctly also.

[paul52446m]

The booster pump only runs when there is a demand for water..seems to work fine in that regard...pipes are sized correctly also.

I am assuming you are on city water? Did you put that booster pump just after the main comes into the house and after the water goes through the filter. Your city pressure is low so when the pump comes on you are sucking water faster than the city pressure can keep up with it so it sucks your filter down some.
Your T&p valve is temp and pressure, so it might be building up too much pressure and popping the valve.
You need to have a pressure gauge in your heater so you can see what the pressure is. You might have to put a throttle valve to turn the pressure down some. You do not want to run more than about 50 lbs to sinks. I don't know if the plumbers will agree with any thing i have said , But doing boiler work of 40 years, i know what that when you bank up pumps you really start building pressure. Paul

[DuneMe]

I'm big on the keep it simple theory. . . Could it be seeing excessive Temperature / Pressure?

Having replaced that valve so much I steer that way.

A gauge like this will give you your highest pressure recoded.
Types 2089, 2086 and 2084 Precision Digital Test Gauges#
Ashcroft makes good gauges.

DuneMe, thanks for your reply...I have replaced the tp twice since the pump install..I'm thinking that's not it. Thinking about an expansion tank now. I had no idea this would cause so many problems!!

[paul52446m]

I'm big on the keep it simple theory. . . Could it be seeing excessive Temperature / Pressure?

Having replaced that valve so much I steer that way.

A gauge like this will give you your highest pressure recoded.
Types 2089, 2086 and 2084 Precision Digital Test Gauges#
Ashcroft makes good gauges.

Keeping simple theory would be going down to the hard ware store and buying a simple pressure gauge It would not be popping off on hi temp in three valves in a row. So all he needs to do is check pressure. So why complicate things with gauges like that!! Paul

[DuneMe]

OK, I'm wrong. . .

Keeping simple theory would be going down to the hard ware store and buying a simple pressure gauge It would not be popping off on hi temp in three valves in a row. So all he needs to do is check pressure. So why complicate things with gauges like that!! Paul

[LazyPup]

Contrary to popular belief there are no pumps generating the municipal water main pressure. The municipal water line pressure is generated by Vertical Static Head Pressure (gravity fall) generated by water towers or storage tanks on high hills within your community.

In essence the municipal water supplier installs a water tower and some point within the community that will provide the code minimum 40psi to the largest segment of the area that it serves. Normally the water tower tanks are large enough that they can hold about a 3day supply of water for their service area (This helps insure a safe water supply even during periods of major power outages and in my community the water service has an old pumper type firetruck that can be used to fill the tanks in an emergency)

At the base of the water tower they install a pump house on the feed line from the wells or primary water source. The tank on top of the tower is then fitted with float switches that work in the same manner as the float switch on a sump pump. As the water level in the tank drops to a set point the pump is started and it pumps water up to the tank until it reaches a preset full point. (Generally the cities also have timers on those pumps so they will primarily run from midnight till dawn during the "off peak" hours to conserve electrical cost.)

See attached Illustration,,

Water weighs 0.434psi/ft vertical.From the illustration you can see that if the bottom of the tank is 100ft above the water main the vertical column of water will generate 40psi pressure on the main, and if the water level is raised to 184' it will generate 80psi on the main. As you can see the level of water in the tank will provide pressure within the code Max/min levels of 80psi max & 40psi min to the majority of the structures within the water towers service area.

Now examine the houses on the left side of the tank. Note that they are built at higher elevalations and there is a pressure drop on the main as it rises. Generally the pressure is still above the code minimum of 40psi, but if the water level in the tank should drop considerably the resultant pressure at those house would then be below the code minimum, therefore we would have to install a "boost pump" to insure 40psi to the house distribution system. (The boost pumps are fitted with both a pressure switch and a flow sensor so if flow is occurring and the pressure is below 40psi the pump kicks in to boost the pressure up.)

Now look at the houses on the right side that are built below the level of the water tower. You will note that as the water main drops elevation it increases pressure and if the water tower is full, the resultant pressure is above the code maximum of 80psi so we then have to install a PRV (pressure reducing valve) to limit the pressure to the code max of 80psi.

This also explains why when you use a pressure gage to measure your line pressure you will not that it is different from day to day. Basically, if you take the reading in psi from your gage and divide it by 0.434psi you will know approximately what the vertical differential is between the point where you measure and the top surface of the water in the municipal storage tank.

[LazyPup]

There is a much easier way to keep it simple. Just accept the fact that as the cold water is heated it expands its volume about 5%. Understanding that all the lines are full, the tank is full and the boost pump has a check valve that prevents the excess volume from backflowing to the main, the volume has to go somewhere because water is not compressible. The increased volume pushes the T&P valve open and the excess volume is relieved.

The solution is to install the code mandated expansion tank on the water heater cold water inlet line, but careful here. The expansion tank MUST BE installed on the water heater side of the water heater cold water shutoff valve.