Water Heater Help - No Pressure

buckle97 · Mar 2, 2010

Now that you all solved my well pump issue, I've got another one for you.

I have a propane 40 gallon water heater (2 years old) that was located in one part of the house and I have relocated it to another part of the house. I replumbed to it, got it vented, hooked up to propane, etc. and now there is hardly any pressure coming out of it. I have 5 hot water faucets in the house and with the exception of the washing machine which is literally right next to the water heater they all have low pressure. I turn on the cold and it has normal pressure, I turn on the hot only and it feels like a little less than half of the cold pressure. Shouldn't they be approximately the same pressure? The washing machine that feels like it has the most pressure on hot just has a hose bib on the pipe so that could be why it feels stronger.

Any suggestions?

bp fick · Mar 2, 2010

Sheer guess without being there, but if if you relocated an older heater and re-plumbed it and this restrictive flow issue surfaced following your work, then something went amiss. I've installed dozens and dozens of water heaters.

Did you downsize to 1/2" pipe on a feed or exit?
Did you inadvertently get something in the connection? Washer wadded up restricting flow?
Did you have, or do you now have cut off valves above the water heater?

Finally though rare, a big old chunk of calcium may have moved is now blocking the flow inside the tank inlet or outlet. You are forced to work this issue now, I'm afraid.

buckle97 · Mar 2, 2010

bp fick said:
Did you downsize to 1/2" pipe on a feed or exit?
Did you inadvertently get something in the connection? Washer wadded up restricting flow?
Did you have, or do you now have cut off valves above the water heater?

Finally though rare, a big old chunk of calcium may have moved is now blocking the flow inside the tank inlet or outlet. You are forced to work this issue now, I'm afraid.

It was 1/2" CPVC before and now it is 1/2" PEX. The low pressure did surface after my work, it was fine before the move. I'm pretty sure all my connections are good and clear. I'm afraid you may be right and something is blocking the inlet or outlet from inside the tank.

heehaw · Mar 2, 2010

pex can kink, causing exactly the situation you are describing, or worse. plus with 1/2 inch pex, the way the fitting go into the pipe, do you get as much area of open pipe as you do with cpvc? i haven't used pex yet, so i ask but don't know the answer to that one?
heehaw

bp fick · Mar 2, 2010

buckle97 said:
It was 1/2" CPVC before and now it is 1/2" PEX. The low pressure did surface after my work, it was fine before the move. I'm pretty sure all my connections are good and clear. I'm afraid you may be right and something is blocking the inlet or outlet from inside the tank.

Well, honestly, and don't intend to appear mean spirited, but 1/2" main through lines in/out of a water heater are inadequate. All main trunks should be 3/4".

Feeding an entire house with 1/2", then supplying off to a couple of sinks, washer, dishwasher, shower, toilet(s) is more than continuous 1/2" can feed. Hot or Cold.

The 3/4" main supply lines though should then reduce to 1/2" when running up to a particular shower, toilet, sink, etc. Then, between the cut off valve for each faucet or toilet, you can supply that singular demand with 3/8"

This keeps the regulation in balance. Does this make sense?

Travelover · Mar 2, 2010

Since most water heaters have one way valves to minimize convective circulation, I'm wondering if it is plumbed backward or if one of these valve / connectors got misinstalled.

/pine · Mar 2, 2010

If the line is not kinked then there is a blockage...

perhaps a piece of mineral build-up that had accumulated in one of the old fittings broke lose etc when you were doing the work...

the size of the pipe may cause a problem with volume but pressure is pressure...you shoule have the same pressure on the hot side as you do on the cold...

[edited]

not trying to be smart aleck...but many new water hearters have plastic plugs that have to be removed befor installation to prevent foriegn matter from getting into the tank...

buckle97 · Mar 2, 2010

heehaw said:
pex can kink, causing exactly the situation you are describing, or worse.

I hadn't thought about a kink, I'll check for that under the house.

buckle97 · Mar 2, 2010

bp fick said:
Well, honestly, and don't intend to appear mean spirited, but 1/2" main through lines in/out of a water heater are inadequate. All main trunks should be 3/4".

Feeding an entire house with 1/2", then supplying off to a couple of sinks, washer, dishwasher, shower, toilet(s) is more than continuous 1/2" can feed. Hot or Cold.

The 3/4" main supply lines though should then reduce to 1/2" when running up to a particular shower, toilet, sink, etc. Then, between the cut off valve for each faucet or toilet, you can supply that singular demand with 3/8"

This keeps the regulation in balance. Does this make sense?

I understand the whole 1/2" vs 3/4" argument but first of all this is a rental house (I know, that's really no excuse) and second of all the entire house was plumbed with 1/2 CPVC when I bought it with plenty of pressure on both the hot and cold sides.

buckle97 · Mar 2, 2010

/pine said:
the size of the pipe may cause a problem with volume but pressure is pressure...you shoule have the same pressure on the hot side as you do on the cold...

[edited]

not trying to be smart aleck...but many new water hearters have plastic plugs that have to be removed befor installation to prevent foriegn matter from getting into the tank...

That's what I was thinking ... pressure is pressure.

This is not a new water heater, it has been used before. I assume any plugs would have been removed for it to work right in its previous location.

/pine · Mar 2, 2010

I doubt this the problem...but you might check the strainer screens in each of the sink faucets...
the last time I changed out a WH a lot of calicum particals broke loos and accumulated in the screens...

buckle97 · Mar 2, 2010

/pine said:
I doubt this the problem...but you might check the strainer screens in each of the sink faucets...
the last time I changed out a WH a lot of calicum particals broke loos and accumulated in the screens...

Wouldn't this also restrict the cold water coming out of the same faucets?

forgeblast · Mar 2, 2010

could it be one of the plex fittings when connected were crimped to much and its causing a low flow. or did you put in a manifold system, maby the valve is not open all the way and your only getting a little flow.
You could put a bucket in the cold intake on the hot water heater and check the flow, if its coming in fine, its your hot water heater. would moving it around caused some minerals/gunk to clog it up?

Boiler74 · Mar 2, 2010

I've replaced the plumbing in two houses with Pex. And I've learned a couple of things, although I don't profess to be an expert. 1/2" pex is not the same as 1/2 copper or cpvc. Because of the way they connect, the restriction comes from the fittings. They go inside the pipe, and then you have the thickness of the metal in the fitting. So it does really restrict flow. I didn't notice it as much with the first house I did because I replaced old galvanized that had restricted flow from rust, etc. But then I redid a house that had copper, and noticed it big time. (The copper pipes had to be redone, I don't just pull it out for the **** of it) Think about it, with cpvc and copper, your 1/2 pipe goes inside the fitting. And 1/2 copper has a thinner wall also. So pex, while great, does reduce flow. For me, next time it will all be 3/4 pex.

Just my experience, and it may not be your problem at all. But if I help one person reading this thread, it was worth the time to write.

Have a good day.

J.

Charlton John · Mar 2, 2010

Same exact thing happened to me a few weeks back. I didnt relocate though but lost all hot water and could only get cold. After removing the pipes that connected into the heater it was discovered it was being blocked by calcium buildup which was like concrete, since I flushed the tank and cleaned the buildup, I am back to normal.

/pine · Mar 2, 2010

Wouldn't this also restrict the cold water coming out of the same faucets

obviously it would on mixer valve applications...but it is always a good idea to clean the screens after opening any lines...

Again, the last time I changed out a WH I had no pressure on the hot side of the washing machine...big clod of minerals in the screen at the solenoid...

with the pex fittings it would not take a very large size piece of material to cause a blockage...if all the service valves are effected then start at the WH and inspect each connection...

Richard · Mar 2, 2010

Boiler74 said:
1/2" pex is not the same as 1/2 copper or cpvc. Because of the way they connect, the restriction comes from the fittings. They go inside the pipe, and then you have the thickness of the metal in the fitting. So it does really restrict flow.

That is what I was thinking as I read through. I had the understanding that if you have 1/2" pipe that you would need something more like 3/4" PEX to "keep up" with the 1/2" pipe because of the inner restrictions.

That said, it's interesting that you have 1/2" going into your heater.

I moved my heater, added a shower in the basement and since I'm on a gusher well (over 100 gallons/minute) I decided to make it a gusher shower. I replaced all the 1/2" pipe and upped it to 3/4" pipe to the shower valve. Bought the 3/4" version of the valve so that everything is 3/4" up until the heads themselves. I then removed the water restrictions in them.

During this process, I had pipes going everywhere. So much so, that before it was said & done, I actually plumbed one of my hot pipes back into a "T" of one of my cold pipes :confused2: I figured that one out pretty quick and fixed it. The other one was more subtle. The stupid plumber crossed yet another pipe and plumbed the toilet into the hot line so anytime you wanted a hiney sauna, all you had to do was flush and you'd get HOT water, fresh from the water heater filling the commode. I even went so far as to tell my father in law I did NOT want to catch him sneaking over to my house so he could steam his buns

This mistake of course, was not caught until after I put the drywall up and taped it and painted it.

Soooooooooooo, one of my weekend projects was the removal of a section of drywall to fix the pipes.

buckle97 · Mar 2, 2010

Charlton John said:
After removing the pipes that connected into the heater it was discovered it was being blocked by calcium buildup which was like concrete, since I flushed the tank and cleaned the buildup, I am back to normal.

I am starting to think, based on numerous replies, that it may be a buildup in the tank restricting the pressure. Can anyone provide the steps I need to flush the tank to get rid of as much of the buildup as possible?

J.Walker · Mar 2, 2010

I just had the problem of low hot water pressure. It was a blockage in the outflow of the tank. I removed the conection to the tank on the outflow side and turned back on the water. The blockage came shooting out with alot of water too! Reconnected the outflow side, problem solved.