Hot Water Air Blockage - Plumbing - DIY Home Improvement | DIYChatroom

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


Thread Tools Display Modes
Old 05-23-2010, 09:08 AM   #1
Join Date: May 2010
Posts: 1
Rewards Points: 10

Hot water air blockage

I have a vented 170 US gallon (650) litre gravity feed hot water storage tank in my ceiling with a 25 US gallon (100 litre) cold water feeder tank mounted about 12 inches further above the top of the hot water storage tank. The water is generally heated by a slow combustion stove. The hot water distribution pipe runs from the top of the storage tank, down an inside wall to underneath the house where it is distributed back up the walls to the various outlets. It is all done in 3/4 inch insulated copper pipe.
Everything runs fine in summer however in winter (40-50 Degrees F.) an air block develops which stops the hot water flowing and only allows a poor volume intermittent flow.
The following events seem to lead to the blockage.
1. Low outside temp (40-50 F.)
2. Low hot water usuage
3. High temperature hot water generated by the stove.

I do not think the water in the storage tank is boiling as I would hear the rumble or see the overflow from the exterior vent pipe. Also I have checked that the vent pipe is not blocked.I have tried leaving one or all hotwater taps turned on but I cannot get the water to flow freely after the air lock develops.

My "fix" is to climb into the roof cavity and loosen the hotwater take off pipe at the "Tee" on the top of storage tank which seems to eradicate an air block and the water then runs normally as I refasten the pipe fitting.
Seems really odd as the vent pipe is attached to the top of the "Tee" and should do the same thing as I am doing when I unscrew the fitting a little and allow the water to syphon down and draw air into the system!

Any suggestions on fixes?


pontiac is offline   Reply With Quote

Thread Tools
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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Water Inside/Around American Standard Furnace michrob HVAC 8 12-08-2011 03:51 PM
Bosch 1600H Tankless Water Heater natemclain HVAC 13 08-24-2009 10:33 AM
Kitchen Faucet Cold Water Runs Hot Mthrboard Plumbing 8 08-02-2009 06:59 AM
How Do I Properly Shock Chlorinate a Water Softner classicflytyer Plumbing 5 07-14-2009 12:15 AM
No Hot Water comeing out of Faucets gangstacro Plumbing 5 11-30-2008 03:32 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1