Versa Hydro Installed-Questions

woodshed

I installed a Versa-Hydro 130-55 a few months ago and the unit's been in heating mode for a couple of weeks; I have a few questions:

1. I'm using a 20* Delta T in the Hydro settings however this raises the tank target temperature by 20* which then also raises the bottom tank temperature. With a top tank temperature of 145* the bottom tank temperature is 130*. Shouldn't the bottom tank temperature be 120* or less to be condensing? If I lower the Delta T to 15* the bottom tank temperature drops to 120* or slightly less.

2. The unit never reaches the tank target temperature; the top tank temperature is 5* lower than the tank target temperature. Is this right?

3. I'm using zone control valves with t-stats for each zone. The system pump is a VT-2218 set for 20* Delta T. The supply temp on the pump is 5-7* lower than what the Hydro shows on the display for supply temp. The temp on the pump is always lower than what the Hydro says the supply temp should be; the supply sensor for the pump is 30" upstream from the supply union fitting on the Hydro. The supplied P+T gauge shows a lower water temp as well.

4. The supply and return temps shown on the VT-2218 are a 30-35* differential (supply 125* and return 95*) even though pump is set for a 20* Delta T; the pump runs in the 56-58 watt range (max). Does this seem right?

5. Since the Hydro is using a FPX and DHW water for for the FPX, how will this unit achieve condensing? I'm getting confused with the top and bottom tank temperatures and how this relates to condensing mode.

7. Is the idea to have the Hydro burner constantly modulating to maintain tank temp or to use the hot water in the tank and run the Hydro burner to get back to tank temperature during a heat demand?

8. I'm using a 20* Delta T for the Hydro; would a tighter Delta T of 8-9* be better with in-floor quik trak tubing.

Thanx for your help

Rich_49

Rick ,

Since you are using a VT2218 and can get no narrower than a 35* Delta and are using 58 watts ( max) I would venture a guess that your circ is not properly sized for the system .

Which settings id you program into the # 600 and which into the 925 setup ?

You must figure the head loss of the HX into the circuit along with the actual piping and emitters . Tank temp should be whatever you programmed into it . 600 program is for water heater and 925 is for space heating functions . The unit cannot be programmed while any call is being seen . Contact me if you'd like to discuss or Tech support will certainly be able to help .

Paul48

The heating modules requirements alone fall outside of the 2218's range.

Rich_49

That would depend upon system requirements Paul . For instance , if the BTUh requirement was 50 K the head loss through the FP would be right around 2 feet .

We have in the past had to employ hydraulic separation to use certain types of circs on the system side . Just when you think you thoguht of everything something bites your butt . It certainly sounds like this may be one of those cases and the sum of the ehad losses of the HX and system are too high .

Paul48

That was somewhat confusing in the manual Rich. It says the module requires 10 ft of head at 12 gpm, and proceeds to use , a system that requires 5 ft of head, would then become 15 ft of head at 12 gpm.

Rich_49

Thats correct , if you need 12 GPM . I don't get what was confusing in the manual , there is a graph showing head loss and GPM just like a pump curve . Am I missing something you are trying to point out Paul ?

The Op stated that he used the 130-55 which limits the output of the module to 100K for heat . I have no idea what his design load is so cannot even venture a guess but it sure sounds like there is a lack of head / flow reconciliation that happened in this case .

Paul48

Certainly nothing smartass or underhanded Rich. I just forget that this was not a typical mod/con with typical high flow requirements. I didn't see that as an example, but as they stated, a requirement. And, then seeing the graph became more confusing. It's just caused by not being familiar with the product. I mis-read it, and once you said it, it became very clear. I know you think these things are clear as can be, but I don't think that those that don't have access to a ready explanation will find it quite as self explanatory.

Rich_49

Sorry for the confusion . Did not think there was anything smart assed or other in your post .

Lotsa confusing or unclear things in almost every manufacturers publications . One must be careful when reading things written by lawyers and engineers that just know they are smarter than the installer / user . Maybe that is why we keep getting better products that cost more to install and actually suck in folks homes

woodshed

Rich said:

Rick ,

Since you are using a VT2218 and can get no narrower than a 35* Delta and are using 58 watts ( max) I would venture a guess that your circ is not properly sized for the system .

Which settings id you program into the # 600 and which into the 925 setup ?

You must figure the head loss of the HX into the circuit along with the actual piping and emitters . Tank temp should be whatever you programmed into it . 600 program is for water heater and 925 is for space heating functions . The unit cannot be programmed while any call is being seen . Contact me if you'd like to discuss or Tech support will certainly be able to help .

Rich -

Here are the 600 and 925 settings:

600:
CH 140
Delta T 20*
DHW Set 119*
Burner Run Offset 5*

925:
Max Tank Temp 180*
Offset 5*
WWSD 65*
Min Outdoor Temp -6*
Max Supply Temp 150*
Max Outdoor Temp 68*
Min Supply Temp 110*
Min Tank Temp 68*
CH Post Pump 0 min

Additional Info:
I'm using four remote manifolds, two on each floor, with flow meters and valve actuators on each circuit (11 zones). When I check the delta T at the individual manifolds, I'm getting a ~20-25* delta T. The higher Delta T's are from the manifold furthest from the boiler room.
In the boiler room in the basement, the VT 2218 is reading 35-40* delta T.

The total heat load is 34,000 btu's, 5 feet of head, 20* delta T. When I look at the Hydro pressure drop chart, at 3.4 GPM, I should add 1 feet of head for a total of 6 feet of head.

Looking at the VT 2218 flow graph, I'm in the lower section of the variable speed range.

I'm also using quik-trak and most rooms are carpeted, wet area's are tile/wood (floor and ceiling joists are insulated).
Rick

Rich_49

How long are the tube lengths on that QuikTrak ? 5/16" tubing needs very short loop lengths , you sure the head is that low for the system segment of this . Got some pictures ? I would lie to see .

woodshed

Rich said:

How long are the tube lengths on that QuikTrak ? 5/16" tubing needs very short loop lengths , you sure the head is that low for the system segment of this . Got some pictures ? I would lie to see .

Rich -

Attached are some pix of the boiler room and the radiant panel report.
The quik trak was installed about 15 years ago and the design was by Wirsbo (Uponor) at that time. I saw the original tubing layout from Wirsbo and when I checked a few of the tubing lengths at two different manifolds they seemed to agree with the tubing layout. I did notice some of the tubing lengths in excess of 200'; I contacted Uponor about quik trak tubing lengths and they stated up to 250' is acceptable. They sent me an essay that does state not to exceed 250' for tubing length. So it appears the tubing was installed within Wirsbo parameters at the time of the design.
Ripping out the floor finishes and running shorter tubing lengths is not an option at this point.
I should also add that the Hydro was a replacement for a 15 year old Voyager that was using variable speed injection mixing with a 008 system pump and a 003 injection pump. The system was able to maintain a 20* delta T.
I'm wondering if I should replace the VT2218 with the 008 and see what happens; the Tekmar 362 is still in the boiler room so I could run the 008 using the Tekmar 362 variable speed signal.
Rick

Rich_49

Could you print the rooms as shown on the tags from left to right ? How long is the length to the remote manifolds ? Do you have any other Uponor reports ? Uponor would have given other reports showing length to manifolds and supply and return pipe sizing , if these were not followed exactly or a few liberties were taken thinking they were not that big a deal , therein might lie your issues .

Your J Office for instance shows a head loss of 4.2' . Is that just the loops and were any other devices added in the circuit , were the # of turns on the valve at the manifold followed exactly . QuikTrak requires precise calcs and installation .

woodshed

Rich said:

Could you print the rooms as shown on the tags from left to right ? How long is the length to the remote manifolds ? Do you have any other Uponor reports ? Uponor would have given other reports showing length to manifolds and supply and return pipe sizing , if these were not followed exactly or a few liberties were taken thinking they were not that big a deal , therein might lie your issues .

Your J Office for instance shows a head loss of 4.2' . Is that just the loops and were any other devices added in the circuit , were the # of turns on the valve at the manifold followed exactly . QuikTrak requires precise calcs and installation .

Rich -

1. The tubing from the boiler room to the 4 remote manifolds is 3/4" Hepex.
S/R Loops: Manifold 1= 120', 0.2 head, Manifold 2= 80', 0.8 head Manifold 3= 64', 0.5 head, Manifold 4= 120', 0.8 head, Manifold 5= 100', 0.9 head. The loop lengths are total supply and return lengths; both ways, not one way.

Adding the highest head loop, 4.2, to the highest head S/R loop, 0.9, is head of 5.1 plus the 1 feet of head for the Hydro is total head of 6.1.

The loop head values include Wirsbo brass manifolds with S/R shutoffs, valve actuators and flow meters.

I did not use "turns of the valve" but rather loop flow from the Uponor program using the flow meters. Although adjusting to flows lower than 0.25 GPM is rather difficult.
Rick

Rich_49

Do your manifold callout numbers correspond with the ones on the report ?

woodshed

Rich said:

Do your manifold callout numbers correspond with the ones on the report ?

Rich -

Boiler room manifold callouts: Left to Right
4 Season=Manifold 5
1/2 Bath=Manifold 1
M Bath=Manifold 3
NW BR=Manifold 4
Hall=Manifold 2

Rich_49

What rooms are on each manifold Woodshed ?

woodshed

Rich said:

What rooms are on each manifold Woodshed ?

Rich -

Look at the manifold summary report.

4Johnpipe

Not sure if this was asked yet...Did you confirm the valves are all open inside the cabinet between the tank, supply return and heat exchanger?

woodshed

4Johnpipe said:

Not sure if this was asked yet...Did you confirm the valves are all open inside the cabinet between the tank, supply return and heat exchanger?

Yes; all valves are open inside the Hydro cabinet.