Water Heaters Project Timeline•May 15, 2006: First discussion of water heater project since warrantees are getting close to expiration

• Discussion of Home Depot Conventional ($1500) vs Indirect ($5000) and group chooses Indirect

• Pam supposed to check with 1 or 2 of the plumbers (contacted previously) and get an estimate including an auto-shut off valve for the “Home Depot” & Steve agrees to do the same with a hockey friend for indirect

•October 2, 2006: Warranty is up in November 2006.

• Group still agrees with indirect system with a goal of having a proposal in hand by the end of November before it gets too cold (heat may need to be off 2-3 days).

• Group agrees to go with Home Depot ($1500 option) with appropriate drip pans if we cannot have the indirect system installed by the end of October.

•February 1, 2007:

• N-Star is not interested in conventional install

• Steve’s friend Mike is willing to do the work in the spring but photos and measurements are required

• Susan and Steve agree to follow-up with photos and measurements so Mike can make a bid.

• Group agrees to go Home Depot if heaters break before indirect can be installed

•November 5, 2007:

• Steve had not heard back from his contact but received a note on Nov 5 that contact forgot about photos and measurements from the summer but could do it in 2 weeks. At this point Steve had to leave the meeting

• Group is very concerned about the lack of progress on this project to this point (~18 months) and discuss waiting on indirect proposal from Steve or going with standard option that can be implemented at any time

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Water Heaters Project Timeline•April 29, 2008:

• Conventional (Home Depot style) proposal with Rick the Plumber estimated at $3000-5000 (not including corroded pipe replacement which jumped it up to ~$6500) communicated by Sarah Hulsey

• Steve brought three indirect proposals: Barrell ($13,000), James Devaney ($20169) & Peter Carriere ($23,233) (plus one unamed bid for $15,000).

• Group was concerned about the cost of these proposals and led to 4 proposals

• 1) = Rick / Home depot + Fix corroded pipes

• 2) = Steve Indirect

• 3) = 1) but add some extra plumbing / re-piping to facilitate implementation of #2 in a year or 2

• 4) = only fix corroded pipes and install new drip pans and save up for #2

• Steve agreed to get bids on 1, 3 & 4 from his 3 guys in 2 weeks for an online group vote

• Sarah H said the Rick probably not interested in anything except 1

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Water Heaters Project Timeline

•June 3, 2008:

• After significant discussion 8 of 8 condo mates agreed to the a 2 stage process to get to an indirect system:

Stage 1:

-Fix the corroded pipes in the mechanical room including into Pam's bathroom.

-Replace the current water heaters with conventional water heaters (high end glass lined).

-Get new metal pans to place under the water heaters that will drain any water out onto the roof.

-Add appropriate plumbing such that any water outflow from the heating system boilers can also drain into the metal pans under the water heaters and out onto the roof. 

-The new system will include an appropriate pressure expansion tank for the boilers and a water sensor with an automatic shut off for the water heaters. 

-Steve in 3A will contact Rick Hoffman (aka Rick the Plumber) to get a clear bid on this proposal. If he does not get in touch with Rick by Wed 06/04/08 he will tell Susan in 2B and she will get in contact with Rick. The goal of the group is to have a final bid by  the end of June 2008.

-If the bid for all of the work is <$8000.00 then we can go ahead directly however if it is >$8000.00 then the proposal will have to be put to another vote of the condo association. 

 

 

Stage 2:

-The condo association agreed that ultimately the indirect system is what we want, however without taking out a group loan which the majority does not want we cannot afford to do it now and still maintain a $10000.00 fund in the bank.

-The association agreed that the 24% increase in fees will be put as a line item in the budgets and go towards saving for the indirect system with the goal of putting it in within 3 years. This assumes that there is no catastrophic event (eg major roof failure) that would take precedence over the heating upgrade (based on the home inspection, none is on the horizon). 3

Water Heaters Project Timeline

Since June 5 2008:

-Sarah H and Susan took over the coordination with Rick

-Rick provided a bid to do the Stage 1 work of ~$6500

-In between June and October, the mechanism or the corrosion became an important issue

-On October 20 Rick said that he could not do the work for us

-At this point the trustees asked Pam to help identify new plumbers from Angie’s List to do the work (which she did) and they gave 2 bids each (both for the original plan (both came in @ ~$6500) and for a simplified indirect system which offers all of the safety advantages but few if any of the energy savings of the Steve proposal(one came in at ~$8300 (Winter) and the other at ~$11500 (Allen)).

-Given that Pam was sick and Leah was new we (the trustees) agreed to have the plumbers only go across the hall but to let us know if they saw more corrosion and that we would have it fixed when we could get Pam and Leah into the loop again.

-The work is now completed with the exception of the Pam/Leah piece which will follow up on as soon as possible

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Some Pipe Corrosion Follow-up

Using Info Provided by Steve Sisak

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From http://www.codewell.com/~sgs/heating/Corrosion_fact_sheet_for_designers.pdf

1 MIL = 1/1000 inchThe best ¾ inch copper pipe (K-grade) has a thickness of 65/1000 inches (http://www.gizmology.net/pipe.htm)

If we assume a water velocity of 8.1 feet/second and a water temp of 120 F the predicted velocity corrosion rate = ~5 MILS / Year

Then it would take 13 years to corrode our pipes and they would have failed 5-6 years ago and we would probably have seen corrosion before that.

There is no mention of serious visible corrosion before 2007

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Table 1 from http://www.codewell.com/~sgs/heating/copper.pdf

According to this document, high velocity alone is not enough to propagate corrosion

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From http://www.codewell.com/~sgs/heating/copper.pdf

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EROSION-CORROSIONRapidly flowing solutions can often disrupt adherent surface films and deposits that would otherwise offer protection against corrosion.  Thinning or removal of surface films by erosion from the flowing stream results in accelerated corrosion, called erosion-corrosion.  The attack is accelerated at elbows, tube constrictions, burrs, and other structural features that alter flow direction or velocity, and increase turbulence.Erosion-corrosion takes the form of grooves, waves, gullies, teardrop-shaped pits, and horseshoe-shaped undercutting in the surface.  The effects of the hydrodynamic are not well understood.  Undercutting may occur in either upstream or the downstream direction.  As described in the schematic below, turbulent eddies thin the protective film locally to produce undercutting, which is seen in the accompanying photograph.

 

Figure 1.  Schematic of turbulent eddy mechanism for downstream undercutting of erosion-corrosion pits. 

Figure 2.  Photograph of erosion-corrosion showing individual teardrop shaped pits with undercutting in the downstream direction.

EROSION-CORROSIONRapidly flowing solutions can often disrupt adherent surface films and deposits that would otherwise offer protection against corrosion.  Thinning or removal of surface films by erosion from the flowing stream results in accelerated corrosion, called erosion-corrosion.  The attack is accelerated at elbows, tube constrictions, burrs, and other structural features that alter flow direction or velocity, and increase turbulence.

Erosion-corrosion takes the form of grooves, waves, gullies, teardrop-shaped pits, and horseshoe-shaped undercutting in the surface.  The effects of the hydrodynamic are not well understood.  Undercutting may occur in either upstream or the downstream direction.  As described in the schematic below, turbulent eddies thin the protective film locally to produce undercutting, which is seen in the accompanying photograph. 

 

http://www.corrosionlab.com/papers/erosion-corrosion/erosion-corrosion.htm