testing Honeywell aquastat unit

Reply

  #1  
Old 01-24-09, 04:00 PM
P
Member
Thread Starter
Join Date: Jan 2009
Posts: 4
Received 0 Votes on 0 Posts
testing Honeywell aquastat unit

How can I determine if my aquatstat is bad? I have a two zone
(Honeywell zone valves) Hydrotherm hot water boiler and I can make it call for heat only when I short across the t & t1 lines.
I have replaced both the motors on the zone valves. The boiler is only three yrs old. I have also replaced the thermo units for both zones. Neither one will activate the aquatstat when Iset them to call for heat. both valves worked for about two days when I first replaced the motors and thermostats. I have rewired both zones from the boiler junction block and followed Honeywells wiring instructions for my zone valves as per their web site. Any help greatly appreciated as this aquastat is $$!
I can activate the aquastat by depressing the switch inside the unit.
 
Sponsored Links
  #2  
Old 01-24-09, 05:22 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
What model aquastat is it?

By the T and T1 lines, you are referring to the thermostat connections to the aquastat?

If so, when you short those two lines and the boiler fires up, and the circ runs, etc, how can the problem be in the aquastat? It's gotta be before that... don't it?
 
  #3  
Old 01-27-09, 06:58 AM
P
Member
Thread Starter
Join Date: Jan 2009
Posts: 4
Received 0 Votes on 0 Posts
You're probably right

Excuse my ignorance here, but since I have replaced both the motors on the zone valves, and the wiring, and the thermos, what else could it be? Aquastat unit is a Honeywell L8148E. I confess that I'm out of my league here, but I'm willing to test and follow advice. BTW, thanks for the quick reply and if I'm slow to get back to you, have other problems that I'm dealing with unfortunately, so not checking in as often as I should.
 
  #4  
Old 01-27-09, 07:40 AM
rbeck's Avatar
Member
Join Date: Jul 2007
Posts: 2,482
Received 5 Votes on 4 Posts
As trooper said if you jump the thermostat connections and the unit fires the aquastat is working. Start checking continuity and voltages on the zone valves. Are the valves opening on a call from the thermostats? Are the end switches being made back to the aquastat?
Not to sound harsh but you admitted you were out of your league and probably spent more money at this point than it would have cost you to call the tech originally. The question is do you continue or bail out and call someone?
If you decide to continue we will help but.......you must be well versed with the use of an electric meter and understand wiring.
 
  #5  
Old 01-27-09, 08:56 AM
P
Member
Thread Starter
Join Date: Jan 2009
Posts: 4
Received 0 Votes on 0 Posts
thanks for the info

Yes, I realize my inadequacies, but i am fairly knowledgable with a volt meter and I have wired my house abd shop, and although this doesn't guarantee I now what I am doing, it does mean I'm not totally ignorant of how electricity works, now I might confess to being a little thick headedwall:
As I stated earlier I did a complete new wiring harness for the zone valves. At this point I suspect my auxiallary 24 volt supply.
But to answer your questions: no, when the thermo calls for heat zone valve does not respond. I will do a complete volt test on the aquastat unit and then on the 24volt aux. I am sure I will be back in touch. I appreciate your patience and the problem
isn't calling in a professional; it is finding a professional who is willing to come out. Not many available in my rural area of alaska and they are extremely busy what with all our very cold weather!!
 
  #6  
Old 01-27-09, 12:06 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Posts: 2,482
Received 5 Votes on 4 Posts
Model of zone valve may be helpful also. As you stated 24v power souce is suspect if zone valves do not respond.
 
  #7  
Old 01-27-09, 03:15 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
You said Honeywell valves... are they 8043 type?

Do you have a feel for how they are supposed to work? It's always good to know that... so...

The thermostat closes, and supplies 24VAC to the motor. The motor opens the valve.

There is a mechanism inside the valve that when it is nearly open, pushes a small switch closed... this is the 'endswitch'.

All the endswitches are wired in parallel, and any one of those switches closing should fire the boiler.

The endswitch is electrically isolated (usually, but some designs differ) from the motor circuit.

So, first things first... if the valve isn't opening, look at the thermostat, transformer, and motor components and wiring.

If the valve opens, but doesn't fire the boiler, look at the endswitch components and the wiring.
 
  #8  
Old 01-27-09, 06:01 PM
P
Member
Thread Starter
Join Date: Jan 2009
Posts: 4
Received 0 Votes on 0 Posts
end switches

NJTrooper and rbeck,
Again, my thanks for your prompt, courteous info; you are very gracious in your patient mentoring of my uphill learning curve!
I can manually trip the end switch on each of the zone valves and the boiler will fire. I have double and triple checked the wiring from the aquastat to each of the zone valves and the thermostats and cannot see that it is not done according to both Honeywells and your instructions that I found you provided on another thread. Both zone valves are Honeywell YHV8043E and are brand new. The thermostats are brand new as well. I
cannot get any voltage reading on the external 24V transformer that is supplying the voltage to the thermostats, but then since the thermostats won't trip the circuit when they call for heat I'm not sure that I should see voltage there. How can I determine if the transformer is supplying voltage to the thermostats? Should I just assume that this 20 yr old transformer is shot and go and buy another one? Again, my thanks for both of your invaluable expertise.
 
  #9  
Old 01-27-09, 06:14 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
If you have 120VAC on the primary side of the transformer, and NO voltage on the secondary side, that would surely explain why the zone valves are not operating! No power, no worky...

How many zone valves? A standard 40 VA transformer will power four of those valves I believe...
 
Reply
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


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