My whn 85 Lochinvar. no priority on the DHW

maybemark

With the help of everyone this last spring. I got and installed a Lochinvar85.
I can not seem to get the DHW as priority.
For those that don't remember from my old posts.
I have an old gravity fed system that was changed to a regular pump system 35 years ago. I still have 3", 2" and 1 12" piping for my system, With suggestion from the guys on the wall, I was told not to have a boiler loop, and just go with the system, and the DHW.

This last spring I put in the 85 and a indirect tank.
Now that heating system is going, I can not get the DHW to be priority.
My 1st question, is my 110 wiring for the pump suppose to go to the system, or the boiler.
I originally had it on system, but when it called for heat while it was also calling for hot water. The number 1 would come on, but, the pumps for the system came on also.
I changed it too the pumps going to the boiler, and then, the 1 would show up and the pumps did not come on,after a short period of time the symbol of a house came around the number 1, , then that activated the heating pumps. and my hot water set point never gets met.
I don't know if I have a wiring problem or a menu problem. At first i stayed with all defaults, then I was playing around with the timing of the DHW and SH.

I need help
suggestions are much appreciated
Mark

Tinman

Mark - Take a look at page 21 of the Service Manual that came with the boiler - specifically SH/DHW Switching Time and DHW/SH Switching Time.

maybemark

I did look at that page, both timing numbers are 30 seconds each
thanks for info

Tinman

Default is 30 minutes. Max is 50 minutes. On both.

maybemark

oh
would yu happen to know about the 110 pump lines, should it go to boiler or system?

Tinman

Page 52, Figure 8.2 of the Installation Manual.

maybemark

that was a huge mistake i made, I changed them to 30 minutes
thank you very much

maybemark

Yes, I see the picture.
it was suggested to me not to have a boiler loop, so the only pumps i have is for heat and for DHW.
So, again I'm not sure where that pump for heat should go.
Originally i thought on the system lugs, but, when it called for heat and for DHW, the pumps remained on for the heat, even shouing just a number 1, without a symbol of a house around it

Tinman

All my WHN's have been piped P/S but it looks like you'd use Boiler Pump And DHW Pump terminals.

delta T

If you go into the installer menu under circulators there are two settings for 'DHW forces system pump' and 'DHW blocks system pump'. Make sure it is set for DHW blocks system pump: yes, and DHW forces sytem pump: no. Also make sure the System pump setting is set to CFH (call for heat) and not WWSD (warm weather shut down)

This only applies if you have the heating circ connected to the system pump. If you have it connected to the boiler pump, it should not matter.

I am pretty sure Stephen is correct, without P/S you should be running the Boiler pump not system. My only concern would be that if the boiler temp satisfies, and the heating call continues the system pump will defintely continue to run, however I am not positive the boiler pump will continue to run past its post purge time. I have never installed a WHN without P/S piping though so I cannot speak from experience. It could be that both boiler and system pump run based only on a call for heat. Any one know the answer to this?

maybemark

thanks guys, this is what i set it for boiler.
Delta
I will check out what you mentioned and correct if it needs to be corrected
I really do appreciate you input
Mark

maybemark

that was it, my timing was off, and keeping it on boiler for the pumps is proper, not system.
It's working great now
Thanks
Mark

delta T

Glad to hear it is running! If you are connected to the boiler terminals, then changing those settings I mentioned will not matter.