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angus242 01-06-2009 07:55 PM

low hot water pressure
I need to give some background on this first.
I bought a foreclosed home back in July....what a pain that was. The house was in pretty good condition but needed a few important items. Biggest issue was no water heater. Here was the catch...the mortgage company wouldn't give us the loan without getting an OK from an independent inspector but also, wouldn't let us dish out any cash to fix the problems. The house was bank-owned and would only sell it to us as-is. Bottom line was with the help of my realtor, I more or less broke in and had my plumber install a new tankless water heater. Problem was because of the foreclosure, the water was turned off at the street level. After the water heater was installed, we could only test for gas leakage as there was no water supply. Also, I was not able to work with a permit because I didn't own the house and the bank (owner) had nothing to do with it. Regardless, I know the plumbing inspector for the town I live in so when the day came to turn the water back on, he showed up too and gave me a verbal thumbs up on the water heater. The city turned the water back on and the independent inspector gave the mortgage company the OK to proceed with closing. At that time, I was not allowed in the house to watch how the inspector proceeded. I can only assume he did a quick check of each faucet to make sure they supplied water. So immediately after closing on the house, I added a whole-house sediment filter and a water softener, never assuming I was going to have issues. Well I did....I mean do. Right after hooking up the filter and softener, I ran the faucet in the masterbath and the hot water pressure was terribly low. After some research, I discovered there a small orifice type filter in the tankless heater. I cleaned that out and got some pressure back. As to properly flush the softener, I ran about 50 gallons through the house via different taps. I started with the master bath which is the closest room to the heater. I got a lot of sediment type stuff that came out of all the fixtures. I had to clear the aerators a few times and the tub and shower with both layered with this sandy material. No one has been able to tell me where or I why I got this out of only the hot water side. Mind you, there was no heater. I actually called the company that winterized the house and asked them what their procedure was. Since the city shut the water off at the street, they didn't antifreeze the pipes, they evacuated them completely. So even if there was some sediment from the original water heater tank, I figured most of it would have been discharged then.
Oh, most importantly, the house is only a few years old. I think it was lived in for 3 years and then sat for about 1 year vacant.
So this past weekend, it the hall bath that I'm renovating, the toilet shut off valve was not cooperating so I shut the main supply off to change the valve. Upon turning the water back on again, I started getting the sediment out of the master bath again. Weird because I have a shut off valve going to the heater which I shut off so when I evacuated the cold toilet supply line, I wouldn't siphon it back out of the hot lines. So the hot lines should have never been tampered with. I had 2 cold faucets open to help drain the line before installing the new shut off valve.
OK, so does any plumber have a clue to why the hot pressure throughout the house is much less than the cold? Everything tells me it has nothing to do with the new tankless heater as both the plumber who installed it and the inspector gave me thumbs up how it was installed. I had 3/4" lines on the old tank supply lines and the new tankless is also 3/4". I can't compare how it was to how it is now because I never saw the hot side run until after we closed on the house. Also, what could this sediment be? I find it hard to believe it's something from after all the work I had done to the plumbing. I could see if there was some debris from when the street supply was turned on but like I said, the water was barely run between that time and the sediment filters I had installed. I checked the sediment filters after 6 months and they aren't any dirtier than I'd expect....and definitely not clogged. I'm at a loss.
BTW, it's a ranch with basement and the street supply enters the house on the east side front, goes to the middle of the house and runs directly west through with branches off for each area. It's 3/4" to just before each fixture where it's transitioned to 1/2". There are no 2 fixtures sharing a 1/2" line anywhere. The water heater is the first object on the east wall before it runs west down the center of the house. The only thing I notice about that is it obviously takes the hot water a bit longer to get the the west side as opposed to the east side rooms which are only a few feet from the heater.
I know this is more likely a question for the contractor site but honestly, if you're not a plumber asking the question, the answer there is usually to just get a plumber. I'd like to know what the heck the problem could be before I start going that route.

Thanks and sorry this was a novel but I thought I needed to supply as much info as possible.


angus242 01-07-2009 06:56 PM

I know it's a long post, but one with a clue???? :(

MrRational 01-07-2009 07:35 PM

didn't read a word of it. try using some paragraphs. organize your thoughts. separate what you know you know from what you think you know. you may even stumble across the answer in the process.

angus242 01-07-2009 08:07 PM

OK, my hot water pressure is low. Any clues?

Leah Frances 01-07-2009 08:48 PM

Mr. Rational was not being a complete and total troll. You have to 'market' your posts some if you want help. Think about it a little bit before your fingers start tapping:

- First and Most important (and I don't think this applies to you) don't ask questions that can easily be answered with a simple google search or by using the search function on the forum.

- Title should mention a specific problem or asks a specific question. "Water heater problem" is not a great title. "Low pressure in tankless water heater" is better. Or sometimes, we just need to let off steam so give a rambling tome a title like, "RANT WARNING - My chihuahua ate my electrical permit"

- Start with your questions not your background. State your goal before you go into the novel. "I need to fix the low pressure in my tankless water heater." Is a great opening statement. "Do I need to get a plumber to fix this problem that happens when... or can I fix it myself?"

- get to specifics that actually pertain to your problem ASAP. Model numbers of appliances, dimensions, circumstances when the problem occurs, your location can often help, duration of problem, etc.

- you have to seem like you are looking for help and want to learn something. So, a short statement about your experience or expectations is good. "I am an enthusiastic DIYer who can comfortably learn about anything, with good directions."

- We all have good house stories - or we wouldn't be online at 9:30pm typing away. But keep things relevant . I am not discounting your problem or your story, but the circumstances of your real estate deal/relationship with inspector/ or most of the information in your post does not help anyone else HELP YOU which is ostensibly what you want.

- Layout, grammar, spelling, paragraph breaks, all matter. No one is going to read a 1000 word post that doesn't have a paragraph break; nor will they READ A POST THAT IS IN ALL CAPS OR IM SPEAK. A simple a good test: Read your post out loud before you submit it.

Last, but not least, quit typing while you're ahead (get it?:laughing:) This site is a invaluable resource - spend some time reading and give it another try.

Baron 01-07-2009 09:21 PM

Hot water causes more flaking and sediment separation in water heaters and pipes and especially temperature valves.

Check the shower temp valves and shut offs in question.
It could be as simple as sediment clogging some valve on the hot water side.

I had a case once where the customer wanted me to change a shower valve that was low on pressure in their master bath but no where else in the house.

I removed the valve internals. cleaned it, shook it a few times to make sure it would float and equalize the temp, and re-installed it to cure what seemed too simple.

If your boiler has an anti-scald valve at the heater check that.

angus242 01-07-2009 09:36 PM

I supplied all information I have. Sorry if it was too much.....:(

The hot pressure is low at every fixture throughout the house.

Sediment only appears after main water supply is shut off and then back on.

There are 2 new whole-house sediments filters AFTER the main shut off.

JDC 01-07-2009 09:38 PM

Ok I'm just taking a stab at this. Without being there to look at things I'm trying to visualize it all....

You said you installed a tankless heater, sediment filter and water softener (if I remember correctly). Is the water heater on a soft water line? Could the sediment you're seeing be resin beads from your softener's resin tank? If so that could also be the reason for the lower water pressure/volume on the hot side as a resin bead will clog the hell out of the orfice(s). If there is air in the lines when a softener is started up...and that air isnt expelled slowly, you can cause the resin beads to flow into the piping. I know because I learned the hard way when I was an apprentice. Boss wasnt happy. lol

I dont I said, its a shot in the dark.

angus242 01-07-2009 11:01 PM


Thanks for the reply. No, it's not the softener resin. I know what those beads look like. This is like a dark sand. It must also have a bit of heft to it. The first time it appeared in the tub, I tried rinsing it down the drain and it won't flow so well. I ended up sponging it out because I didn't want it to settle in any P traps.

Joe F 01-08-2009 11:01 AM

I know this is a bit of work, and a "real" plumber probably has a better method, but...

I'd check the pressure with a gauge on both sides of the water heater (might have to cut some lines or disconnect the heater). If that's good, I'd find the faucet closest to the heater with low pressure and work my way back to the water heater. The problem should be in there somewhere.

angus242 01-08-2009 11:41 AM

Thanks Joe,

That's kind of what I was thinking would be a good way to go. A lot easier to try and check for pressure to see where the problem lies than to keep guessing. I do have spigots on either side of the water heater (did that to be able to flush it out).
Still wondering where the silt came from and where it's residing right now.

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