Anyone familier with using a Vitodens 200 with external DHW pump?

The Wire Nut

I was brought in by the contractor on a gut reno to wire up manifolds, t-stats and boiler controls. It's a basic system, with a couple of floors of radiant and some radiators. It has 3 zones controlled by Uponor (OEM from tekmar) t-stats and 3 sets of manifolds with thermal actuators.



The boiler is a Vitodens 200 with a Stibel/Eltron DHW tank with an additional Solar exchanger.



The rep firm that designed it did not provide any wiring diagram so the plumber and electricians bowed out.



Being "The Wire Nut" I accepted the challenge. 



As it turns out, it's not all that complicated though no wires were run between the manifolds and the boiler! The t-stats were cabled to the manifolds but that was it... So, walls are being opened to correct that issue...



However, there is a Taco 007 (or so) on the return from the DHW tank. From what I can tell there is no way to control that pump from the Vito 200, even with the expansion board. However, a couple of the piping diagrams in the installation manual show what appears to be an external pump.



I realize that there is a DHW Production Kit that allows the internal pump to provide for the tank on a priority basis. Is there then any need for the external pump? What if you don't want priority?



Any insight would be greatly appreciated...



Thanks!



Alex (Wire Nut aka "stonehouse") Marx...

CMadatMe

You Have to Use

Viessmanns DHW Kit. Suggest you get on the phone and find one. No way out of it. I don't have my book with me this morning or I would give you the part number. On the new Vitodens 200 you do not need this.

Since we are unable to post PDF's I can't  post the manual. In about a 1/2hr from now I will be unavail. It is also not avail on [url=http://www.viessmann-us.com]www.viessmann-us.com but you have to be a partner to get to the back side of the site.

The Wire Nut

DHW...

Chris,



I requested that they order the kit, after a surprised rep checked and found out that it was needed. Nothing like designing a system and not spec-ing all the parts needed for a "basic" system design... It's been ordered and I'll have it Monday.



I went through the manual pretty carefully once I dug it out of the pile of install detritus in the boiler room. I think they used it to wipe their feet, or clean pipe dope off their hands. Or both.



In the manual there are piping drawing that appear to show external DHW pumps, and one that shows a drawing of the boiler with 2 external pumps affixed to the bottom of the boiler. I know the expansion module will run an external "system" pump, but there is nothing about a DHW pump...



Funny that Viessmann doesn't post an I&M manual like most manufacturers. They have a "Technical" manual and the British version of the I&M is downloadable (found via Google). Liability?



Alex...

Paul Pollets

Vitodens

the 6/24 and 8//32 models do not require an external DHW pump.  The larger models do.  The coding for the internal pump allows you to control the speed of the pump both for heating and DHW. If you  have never programmed the control, I'd suggest talking to Viessmann tech services while doing it. 



The documents are titled "Installation and Service Manual", which give the details for all phases of the install and programming codes.  The document is available online.. Get the password to the site from your rep, or call Viessmann. 

The Wire Nut

Info...

Thanks Paul! That's far more useful information than I got from the rep! It is an 8-32 so I think we're in good shape once we get the DHW production kit.



I suppose I shouldn't be surprised that people "design" and sell stuff that they have no clue about... Everyone needs a job!



Thanks again!





Alex...

heatboy_30

In some instances.......

.......an external pump may be used with a high pressure drop indirect heat exchanger. That may be what you have, if it's an 8-32. It included a relay that was wired into the diverting valve circuit.

The Wire Nut

Relay

I do believe it's an 8-32, however, it didn't come with a relay, nor a DHW sensor. I know the sensor comes with the DHW production kit, but do I need to order the relay as a separate item?



Thanks again...





Alex

Paul Pollets

Viessmann system design

Very few wholesalers have the background to completely spec product requirements.  The Viessmann factory reps do.  If the wholesaler has sent the sales team for factory training, it's most helpful.  The Vitodens requires specific parts to do certain things....  i.e., the DHW production kit, low loss header; additional mixing valves, remote control thermostat, etc.

Paul Pollets

DHW Production Kit

The kit includes all parts to connect an indirect DHW tank. 

Gary Jansen_4

I've done it a couple of times

typically with a different manufactureres tank as part of an existing setup. The kit you need is a Viessmann 7134 599. It provides a relay you wire in series with the dhw solenoid to power an additional dhw pump. Any questions feel free to call me at 920 277 0130. Good luck, Gary

CMadatMe

Do you have access

To the back end of the web site. If so, it's there. Also, we are selling the new 200's and all you now need is to order the sensor for domestic hot water. No more pump module.

The Wire Nut

Time on my hands... Or, what's that smell?

Thanks to all the help and advice...



I installed the DHW production kit and got the boiler wired and connected to the LWCO and the hi-temp limit switch.



The plumber leaves at this point.



The contractor turns on the gas, and purges the line. I wait outside. I suggest they check the other floors for gas.



It fired up, and I set the time and date. It ran through it's tests and fired up on DHW. Unfortunately it wouldn't kick the DHW diverter solenoid and it pumped the hot water through the low-loss header and eventually triped the hi-limit...



Go through the manual, run tests, call the rep, check sensors, factory default it, reprogram, etc. Out of the blue the solenoid starts working, but we can't get it to fire. Check everything all over again, clear a couple of faults, but no go...



Two hours into this, I suddenly realize that the factory default reset the time to 23:00 hours. The default DHW production time stops at 22:00 hours! Reset the time. Bingo, we have DHW!



Contractor goes upstairs to check for Hot Water. Comes down and asks me to see if I smell something upstairs. Yup, gas. Leaking in the wall, with an audible hiss. Windows are opened and gas shut down.



Tenant is again withouth DHW. I'm not going back until the gas line is fixed and tested.



I prefer wire to pipes!



Alex...

Jean-David Beyer

gas. Leaking in the wall

Contractor goes upstairs to check for Hot Water. Comes down and asks me

to see if I smell something upstairs. Yup, gas. Leaking in the wall,

with an audible hiss. Windows are opened and gas shut down.



When my contractor installed the gas line from the meter to my new gas boiler, the gas company would not even allow a connection to the meter until the line was pressurized to 15 psi with either air or nitrogen, with a (brand new) Schrader valve and a (brand new) pressure gauge on it. It had to hold the pressure for at least 24 hours. That was on a Friday when they were taking out the old boiler.



It did not, so they had to find the leak Monday morning. It did not hiss; the leak was so slow none of us could smell it either. The good part was that all the pipes were in the open and there were few joints. Some soap slop on the joints found the leak. They tightened it, Then repressurised it, and the gas inspector approved it Tuesday morning.



Is the gas code so different elsewhere? It seems this should be a reasonable procedure for all gas connections.

CMadatMe

Who installed the boiler

you or the plumber? I take it you were there to wire the boiler up.

The Wire Nut

Gas and wires...

Apparently they had tested the line. But between that time and bringing it on-line, one of the other trades cut through it. I'm not sure how they did it, or what they used, or how they could not know they were cutting through 2" steel pipe...



I found this out today when they called me up about turning on the boiler (which had a jammed power switch)...



I just wired it. My impression is that the plumbing contractor had never installed a Viessmann before and required the rep to come out and show them what to do. The electricians refused to wire it, though most of the wiring was just the LWCO and Hi-Temp switch, all 120 volt items.



The back end is just some Uponor (tekmar inside) t-stats controlling some thermal motors and an TACO iMixer and system pump. Not too complicated but it was more than they wanted to handle...



All in a day's work...



Alex...

The Wire Nut

Thanks...

Gary,



Thanks for the offer of help! If I run into any more issues you may hear from me yet!





Alex...