Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-12-2009, 07:21 PM   #1
Newbie
 
Join Date: Dec 2008
Posts: 28
Share |
Default

Water pressure low and won't stay hot.


I have an older oil boiler that also supplies our hot water. Heating system seems to work fine now but the hot water gets hot and when running for a bath seems to cool down a bit after running about 3 gallons. Not cold but luke warm I have the aquastat set at 150 low and 180 high, and the pressure on the gauge says 21 lbs. Releif valve is new, zone valves are new but one person told me the expansion tank could be full???? He said to tap on it and if it sounds hollow it's okay but if it sounds full or solid I should attend to it. Whatever that meant. Is there and back flushing that should be done? What can I check to locate the problem? Thanks.

Bearcamp is offline   Reply With Quote
Old 01-12-2009, 07:47 PM   #2
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


Quote:
Originally Posted by Bearcamp View Post
I have an older oil boiler that also supplies our hot water. Heating system seems to work fine now but the hot water gets hot and when running for a bath seems to cool down a bit after running about 3 gallons. Not cold but luke warm I have the aquastat set at 150 low and 180 high, and the pressure on the gauge says 21 lbs. Releif valve is new, zone valves are new but one person told me the expansion tank could be full???? He said to tap on it and if it sounds hollow it's okay but if it sounds full or solid I should attend to it. Whatever that meant. Is there and back flushing that should be done? What can I check to locate the problem? Thanks.
The only thing you listed that has to do with the domestic water is the water temp of the boiler. The 150 seems a little low but could work. Do you draw water direcly from the coil in the boiler or is there a mixing valve on the piping to cool the water temp if to hot.

JohnH1 is offline   Reply With Quote
Old 01-12-2009, 07:49 PM   #3
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


I just saw you also have low water pressure. Is that just on hot or cold also.
JohnH1 is offline   Reply With Quote
Old 01-12-2009, 09:25 PM   #4
Newbie
 
Join Date: Dec 2008
Posts: 28
Default

Water pressure low and won't stay hot.


I will post pics of the system tomorrow night Thanks Bill
Bearcamp is offline   Reply With Quote
Old 01-12-2009, 10:01 PM   #5
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,843
Default

Water pressure low and won't stay hot.


Quote:
Originally Posted by JohnH1 View Post
I just saw you also have low water pressure. Is that just on hot or cold also.
Thats the pressure in the boiler, not the wate lines.

At 21 PSIG, thats enough boiler water pressure for a 4 story building

But has nothing to do with teh domestic water.
beenthere is offline   Reply With Quote
Old 01-12-2009, 10:04 PM   #6
Newbie
 
Join Date: Jan 2009
Posts: 13
Default

Water pressure low and won't stay hot.


try getting your heating coil cleaned.
thelimit is offline   Reply With Quote
Old 01-12-2009, 10:29 PM   #7
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


Quote:
Originally Posted by beenthere View Post
Thats the pressure in the boiler, not the wate lines.

At 21 PSIG, thats enough boiler water pressure for a 4 story building

But has nothing to do with teh domestic water.
His title says low water pressure.
I assume he is refering to low water pressure on the hot or cold or both. Most likly the hot indicating a possable calcified coil.
I agree the boiler pressure is to high. But that is another issue to solve after the domestic water.
JohnH1 is offline   Reply With Quote
Old 01-13-2009, 05:24 AM   #8
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,843
Default

Water pressure low and won't stay hot.


Quote:
Originally Posted by JohnH1 View Post
His title says low water pressure.
I assume he is refering to low water pressure on the hot or cold or both. Most likly the hot indicating a possable calcified coil.
I agree the boiler pressure is to high. But that is another issue to solve after the domestic water.
Many people with tankless coils in their boiler think that the boiler water is the same as the water in their potable water pipes.

Bet a cup of coffee he was talking about the 21 PSIG in the boiler, and not his tap water.
beenthere is offline   Reply With Quote
Old 01-13-2009, 12:16 PM   #9
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


Maby,
He may have also had a problem with the boiler since he stated the boiler is now running ok. Who Knows
JohnH1 is offline   Reply With Quote
Old 01-13-2009, 04:58 PM   #10
Newbie
 
Join Date: Dec 2008
Posts: 28
Default

Water pressure low and won't stay hot.


I get my water from a well and seems to be only low at the tub. But anywhere you run it, it's only hot for a limited amount of time then cools off. What's involved in cleaning the coils?
Bearcamp is offline   Reply With Quote
Old 01-13-2009, 05:21 PM   #11
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Default

Water pressure low and won't stay hot.


your domestic hot water is common in the temperature of the boiler only.the cold water line to the coil in the boiler picks up the heat of the boiler and that is considered the start of your hot water piping.your saying you have low temp and low water pressure on the hot water side of your sinks and shower/tubs.you might have a restriction just at the point where the copper line connects to the boiler coil on the boiler.if you have a cold water spigot down from there and you see a good solid pressure then your restricted on the coil.....did you noticed it getting worse as the years went by?bet it is mineral buildup right where the copper is threaded into the back of the hot water coil tank on the boiler.
biggles is offline   Reply With Quote
Old 01-13-2009, 06:37 PM   #12
Newbie
 
Join Date: Dec 2008
Posts: 28
Default

Water pressure low and won't stay hot.


I just bought the home about 2 months ago and noticed it right aways. I'll do the test right aways and let you know. I do know this thing loves it's oil.
Bearcamp is offline   Reply With Quote
Old 01-13-2009, 07:27 PM   #13
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Default

Water pressure low and won't stay hot.


if you can prove solid pressure on the cold into the heater the heat on the coil that gets it heat from the boiler could be restricted giving you a low pressure and in results of low temp combo.
biggles is offline   Reply With Quote
Old 01-13-2009, 09:42 PM   #14
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


Quote:
Originally Posted by biggles View Post
if you can prove solid pressure on the cold into the heater the heat on the coil that gets it heat from the boiler could be restricted giving you a low pressure and in results of low temp combo.
Wouldent low flow only affect pressure? low flow through the coil will allow the water more time to pick up the heat from the boiler.
JohnH1 is offline   Reply With Quote
Old 01-13-2009, 09:45 PM   #15
Member
 
JohnH1's Avatar
 
Join Date: Jan 2009
Location: Chicago, IL.
Posts: 428
Default

Water pressure low and won't stay hot.


Check the pipe temp were it exits the coil to see if it is getting cooler there near the coil or further out in the delivery system somehow mixing somewere with the cold water.

JohnH1 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.