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Paul Pollets

Paul Pollets

Joined on July 24, 2003

Last Post on April 12, 2014

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@ December 16, 2013 11:40 PM in New Solar DHW System for NW School

The flowmeter was specified by the mechanical engineering team based on average flow rates from the heat exchanger into the storage tank. We're about to set up the internet connection this week which will allow monitoring. From what I've observed, flow rates vary between 2 and 5gpm in December. The array produces 110 degree water when ambient temp is 25.


@ December 13, 2013 5:02 PM in Friday the 13th Boiler Failure

I'm moving the shop within 6 months and probably will take the appliance with me, since I was responsible for tenant improvements. The new tenant may want to buy the system.
The shop has 3 loops of Pex in the floor... not much of a load.

Friday the 13th Boiler Failure

@ December 13, 2013 2:34 PM in Friday the 13th Boiler Failure

Gotta figure it's the "Shoemaker's Shoes"...the boiler in our shop failed this AM with a leaking heat exchanger after 10 years...(A Munchkin T50) despite yearly cleaning and maintenance.
The replacement will be a Vitodens 100-26.


@ December 11, 2013 6:08 PM in Italians show comfort

The former...not the latter. When the marketing is more interesting, the sales are likely to be better.

BTU metering

@ December 4, 2013 9:53 AM in BTU Meter

Ista makes a quality meter. I've used their systems several times. There is no such thing as
an inexpensive meter. The savings of using one boiler rather than 5 more than covers the costs. Pay the Piper or divide by 5.

Apprenticeship Model

@ December 1, 2013 12:05 PM in Apprenticeship Model

If this model was applied to the Plumbing and HVAC trades, we'd solve the tech shortage...

Mixing Valve

@ November 28, 2013 12:01 PM in Viessman Vitola 200-DHW but no radiant heat

The 4 way won't do well without the motor actuator & #2 sensor. Someone didn't understand the design & equipment requirements when installing this system. Viessmann prefers constant circulation with their systems...telestats are to be used sparingly, not on every port.
At least there is barrier PEX.


@ November 26, 2013 11:07 PM in Viessman Vitola 200-DHW but no radiant heat

You have a Divicon pump module on the boiler. The Divicon has a motorized actuator. You have a Viessmann 4 way mixing valve without a motor actuator or a pump. Why? The heating circuit will have a hard time getting warm with out a pump on the mixing valve supply. You'll need a pro with Viessmann experience to help you with this. If the tubing does not have an 02 barrier, the system will not last long.


@ November 21, 2013 7:28 PM in How Does this Install Look?

1. Not "pumping away", which adds air to system
2. 1 (Smart) pump and 5 zone valves would have used 70% less power
3. No pipe insulation
4. No outdoor rest control

Otherwise, the system was assembled with some craftsmanship, but there's more to it than shiny copper and a row of pumps.

Indirect failure

@ November 18, 2013 9:48 AM in buderus / logalux blowing off water

You most likely have a failed heat exchanger in the DHWTank. The tank must be replaced. Depending upon age, Buderus offers a pro-rated credit against a new tank. They do not pay any labor costs.
Since the Buderus tanks are not stainless steel, I offer the customer a choice: either a Buderus replacement with a 7-12 year life expectancy, or a new Stainless indirect that should last 50+ years or longer...


@ November 17, 2013 11:22 AM in New Construction Tankless Heating

Not enough detail to see all components. Don't see a 30# PRV on the system side of the FPHX. It seems to be piped for a manual fill.


@ November 17, 2013 10:26 AM in New Construction Tankless Heating

At least the system has a FPHX for system separation. Unfortunately, non-barrier tubing was used on the radiant side. That means the FPHX will need to be used when appliance is replaced.

Red Link

@ November 17, 2013 10:12 AM in WIFI STATS ?

The Honeywell Red Link is easy to integrate.

The new Viessmann B2HA condensing boilers have iPhone capability.

AHR vendor list

@ November 16, 2013 11:01 PM in Viessmann

Chris, here's the list I was looking at:

Supplemental Heat

@ November 16, 2013 2:26 PM in monoflo

This bathroom will require supplemental heating. The pex can do some floor conditioning, but it will never be warm enough with 80' pex. Not even close. Add a towel bar, wall panel or toe-kick convector. I wonder if plates were used?


@ November 16, 2013 11:45 AM in Viessmann

I was surprised not to see them on the vendor list. On the other hand, the product is poorly represented in the NW but at least Ferguson picked up the line and has a decent sales force.


@ November 15, 2013 9:46 AM in How to control radiators in a 1 pipe hot water system

Without re-piping the radiators to either a reverse-return or supply- return, you won't be able to add TRV's. Re-piping in heating season is not the best idea.
You can control the output by setting the heating curve on the boiler correctly, but will not be able to fine tune on a room by room basis without TRV's. Monoflo one-pipe systems don't have much leeway. If the radiators were sized incorrectly, it's hard or impossible to balance the system.
Re-piping is costly, and in a finished space creates inconvenience. If you want ultimate control you'll have to bite the bullet. If not, you'll have to see how your system responds by adjusting the heating curve.

Mod-Con Boiler Considerations

@ November 12, 2013 12:34 PM in Mod-Con Boiler Considerations

From this month's Reeve's Journal:

Near Boiler Piping

@ November 11, 2013 8:48 PM in Radiant floor heat not heating properly

The TT boiler needs an 11/4" primary loop using (1) circulator; any additional secondary zones are taken off the primary loop with closely spaced tees. The primary loop will be set for the highest temp required; zone temps are controlled by mixing valves for RFH zones. Each "takeoff" with closely spaced tees requires a separate pump. Use a variable speed pump for best results, especially if the zone uses zone valves.

See page 21:


@ November 11, 2013 1:23 PM in Viessmann low loss header substitution

Why can't the company that sold the appliance provide one?
The smallest LLH sold has a max flow of 17gpm.
If the Caleffi hydraulic separator is used, the sensor can be strapped to the system supply outlet of the device

Pipe size

@ November 9, 2013 11:59 AM in Viessmann Vitodens 200 setup

I'd connect to the system side of the LLH with 11/4" pipe with 11/4 circ flanges on Alpha pump. You could use 1" piping if you're confident of correct flow rates. If you do the TRV's, system balancing will be very easy. Place any Vitotrol thermostat in the ambient area. If the Vitotrol sensor is enabled and the room has a radiator with a TRV, the TRV must be left at "5" or fully open, or the thermostat will not respond accurately, nor will boiler water temps be as low as they could be.

Vitodens 200

@ November 9, 2013 9:49 AM in Viessmann Vitodens 200 setup

I don't know if you're a homeowner or contractor, but the Vitodens 200 needs to be piped exactly the way the schematics show in the various examples given in the installation manual. The boiler works by sensing the outdoor temperature and the outdoor sensor is fully capable of running the system without a thermostat, providing the heat emitters have been sized correctly. If you have radiators, change the valves to TRV's while the system is drained down.
The boiler can be operated by either of 2 Vitotrol thermostats offered. Both can be configured to give feedback to the computer, if needed or desired. Conventional thermostats cannot be connected to the 200. The new models can be configured to an iPhone app.
The pump between the LLH and the boiler is usually a 15-58 Grundfos or equivalent and the system pump should be variable speed. I use the Alpha pumps. Pipe size is dependent upon required flow rate to the system. Without a heat loss, it's guessing to say the 2" main is oversized.
Your description of the existing system is from the late 1940's or 50's. Bringing the system into the 21st century requires a thorough understanding of how it works and how to pipe it correctly. If you take shortcuts, expect problems. If you do it right, it will deliver amazing efficiency.
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