No hot water after 4 minutes - Tankless Coil


  #1  
Old 03-11-13, 04:48 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
No hot water after 4 minutes - Tankless Coil

I have an oil fired furnace with a tankless coil to heat hot water. After it leaves the tankless coil there is a mixing valve after it leaves the boiler. I have about only 3-4 minutes of hot water when showering in either shower. I have the high and low temp. dials set at 180 and 160 respectively. There is no sight glass on my boiler to see what the water level is. What is my next step here? How do I get longer hot showers? I understand that the coil could be "Limed-up." How easily are these coils replaced? What is the approx. cost of a coil? Is this the best way to get hot water?
 
  #2  
Old 03-11-13, 04:51 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
For the money spent on getting the Thankless coil fixed up it will be better spent on installing an electric water heater....


The others will chime in if your interested in troubleshooting the coil...

'Oh what is the diff set for in the aquastat.????
 
  #3  
Old 03-11-13, 06:36 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
The differential set for in the Aquastat?? Not sure what you mean here.
 
  #4  
Old 03-11-13, 07:27 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
You have a diff setting. This holds off the circ when there is a call for heat to let you have more HW longer. And changes the lo diff from what I know.


 
  #5  
Old 03-11-13, 07:37 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Oh, right. I wrote that in the initial description, 180 high side 160 low side. I called them temperature dials, just read Thermo-dynamics installation manual and that called it the Aquastat as well
 
  #6  
Old 03-11-13, 07:40 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Differential is set at 10, had to go check it
 
  #7  
Old 03-11-13, 08:00 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
Put it on 20, or 25... Let us know how the shower is....
 
  #8  
Old 03-11-13, 08:04 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
What will changing that dial to 20 or 25 do?
 
  #9  
Old 03-11-13, 08:19 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
It will hold off the circulator on a call for heat. So if you taking a shower and the heat comes on you will get a cool shower. Setting the diff higher will get you a longer shower in the winter months.

The heat call will not take away from a HW call.

Additionally is there a mixing valve on your system?
 
  #10  
Old 03-11-13, 08:20 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,159
Received 69 Votes on 61 Posts
  #11  
Old 03-12-13, 02:48 PM
M
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Thanks, that website helped explain a lot. Ill try the diff. dial at 20 -25 and see how it effects the length of hot water we get. Yes there is a mixing valve, I'll be sure to set that correctly so we don't get scalding hot water. Thanks for all of your insight. Mike from PA
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: